Pegasus XL rocket to carry out Tactically Responsive Launch demo for Space Force

Northrop Grumman’s air-launched Pegasus XL rocket will make a low-profile launch for the US Space… The post Pegasus XL rocket to carry out Tactically Responsive Launch demo for Space Force appeared first on

Pegasus XL rocket to carry out Tactically Responsive Launch demo for Space Force

Northrop Grumman’s air-launched Pegasus XL rocket will make a low-profile launch for the US Space Force Sunday, in a mission designed to demonstrate the ability to call up and conduct a launch at short notice. The launch is expected to occur off the coast of California, during a six-minute window opening at 01:09 PDT (08:09 UTC).

Sunday’s mission is designated Tactically Responsive Launch 2, or TacRL-2. The primary objective of the mission is to demonstrate an ability to call up a satellite to launch at short notice. The actual operation of the satellite – specifics of which have not been disclosed – is secondary to this demonstration.

While this is the first mission for Tactically Responsive Launch, a similar test was conducted with the Operationally Responsive Space Office’s Jumpstart mission in 2008. For Jumpstart, several payloads were prepared for launch with the final selection being made less than a month before the rocket was due to lift off.

Jumpstart – which eventually selected the Missile Defense Agency’s Trailblazer satellite as its payload – was launched on the third flight of SpaceX‘s Falcon 1 rocket but failed to reach orbit after an anomaly during first stage separation.

Falcon 1 Flight 3 lifts off as part of the Jumpstart mission – via SpaceX

With TacRL-2, the Space Force have revived this concept. Planning is already underway for at least two further Tactically Responsive Launch missions to fly in the next few years.

TacRL-2 Updates
  • Commercial Space Forum Section
  • L2 Future Vehicles Section
  • Click here to Join L2
  • Very few details about the payload itself are known – other than that it was procured in less than a year, using off-the-shelf components, and will be used for technology demonstration relating to “space domain awareness” – typically a euphemism for monitoring the activities of other satellites.

    The project is being managed by the “Space Safari” office, whose establishment within the Special Programs Directorate of the Space Force Space and Missile Systems Center was announced earlier this month. Space Safari mirrors the Air Force’s Big Safari program, which is dedicated to the rapid development of special mission aircraft using existing airframes and off-the-shelf technologies.

    Pegasus is a three-stage rocket which was originally developed by Orbital Sciences Corporation (OSC). The US Navy had previously experimented with air-launched rockets in the 1950s as part of Project Pilot, but all six of its launch attempts ended in failure. When Pegasus made its maiden flight in April 1990, it became the first air-launched rocket to reach orbit.

    Pegasus uses Orion 50 solid rocket motors for its first and second stages, with an Orion-38 third stage. The first stage is fitted with aerodynamic surfaces, including a triangular wing and a tail with movable fins, to provide stabilization and control during the early stages of flight. All three motors burn hydroxyl-terminated polybutadiene (HTPB) propellant.

    The second Pegasus rocket under the wing of NASA’s “Balls 8” NB-52B aircraft – via NASA

    The first five Pegasus rockets were dropped from NASA’s NB-52B aircraft, named “Balls 8”, before launches switched to Orbital’s own dedicated aircraft, Stargazer. This aircraft, which carries registration N140SC, is a Lockheed L1011-1 TriStar which first flew on 22 February 1974 and was delivered to Air Canada the following month as C-FTNJ.

    In February 1982 the aircraft was briefly leased to Air Lanka, returning to Air Canada seventeen days later. Stargazer was acquired by Orbital Sciences in May 1992. Pegasus is carried and released using a special mount built into the bottom of the aircraft’s fuselage.

    The name Stargazer was chosen as a nod to Star Trek: The Next Generation. It is named after the USS Stargazer, a ship which Captain Picard had commanded before becoming Captain of the USS Enterprise. His First Officer, Commander Riker, had previously served aboard the USS Pegasus.

    The Lockheed TriStar was developed as a three-engine widebody airliner to compete with the McDonnel Douglas DC-10 and the larger four-engine Boeing 747. It has three Rolls-Royce RB211 turbofan engines, one mounted under each wing with the third at the rear of the fuselage and fed air via an s-duct from an intake built into the front of the tail. Despite being one of the most technologically-advanced aircraft of its era, the TriStar was commercially unsuccessful and only 250 were built. Today, Stargazer is the last airworthy example.

    Orbital Sciences’ introduction of Stargazer coincided with the maiden flight of the upgraded Pegasus XL rocket, which featured stretched first and second stages compared to the original configuration and redesigned horizontal stabilizers to ensure adequate clearance for Stargazer’s landing gear to retract.

    Orbital initially offered the Pegasus H – a modified version of the standard Pegasus retrofitted with the XL’s tail modifications – alongside Pegasus XL. The original Pegasus made one more launch in 1994, while the hybrid version was used for four flights between 1995 and 2000.

    While Pegasus uses only solid rocket motors, a four-stage version was developed incorporating the liquid-propellant HAPS upper stage. This allowed payloads to be delivered to higher orbits which Pegasus could not reach on its own. HAPS was last flown on Pegasus in 2005, and although no announcement has been made, it is unlikely to be present on Sunday’s mission.

    Of 44 flights prior to the TacRL-2 mission, Pegasus has completed 39 successfully, with three failures and two partial failures. All of these incidents occurred on early missions: the partial failures came on the second and fifth flights of the standard Pegasus in 1991 and 1994, which reached lower than planned orbits because of issues with the HAPS upper stage. The first two Pegasus XL launches in 1994 and 1995 both failed to achieve orbit.

    The type’s most recent failure occurred in November 1996 when a third-stage electrical fault prevented the payload of a Pegasus XL vehicle from separating. This resulted in the loss of NASA’s HETE satellite and Argentina’s SAC-B, which had shared the ride into orbit. Since then, Pegasus has achieved a run of 30 consecutive successful launches.

    Sunday’s launch will be the first for Pegasus since October 2019, and only the fifth launch of the veteran rocket in the last twelve years. Its last mission was the successful – though much-delayed – deployment of NASA’s ICON ionospheric research satellite.

    Stargazer and Pegasus XL arrive at Cape Canaveral prior to the launch of ICON – via NASA

    Although Pegasus was offered for commercial launches, and a small number of commercial missions were flown for companies including Orbcomm, Orbimage, and the national space agencies of Brazil and Canada, the majority of its flights have been for the US Government, including the Air Force and NASA. TacRL-2 is its first mission for the United States Space Force, which was formed in late 2019 from the former US Air Force Space Command.

    A ground-launched version of Pegasus has also been developed. Initially called Taurus, and later renamed Minotaur-C, this removes the rocket’s aerodynamic surfaces and mounts it atop a TU-903 or Castor 120 booster. This can carry a payload two to three times greater than Pegasus inside a larger payload fairing.

    The Orbital Boost Vehicle used by the Missile Defense Agency’s Ground Based Interceptor anti-ballistic missile (ABM) program uses the same three stages as Pegasus without aerodynamic surfaces. A two-stage version without the third stage can be deployed from the rear cargo door of a C-17 Globemaster transport aircraft to serve as a target for ABM tests.

    The larger four-stage Minotaur I rocket uses the two upper stages of Pegasus, and on some launches the payload fairing, mounted atop the first two stages of a decommissioned Minuteman II missile, for orbital launches.

    Northrop Grumman acquired Pegasus along with the rest of OSC’s fleet of rockets in its 2018 merger with Orbital ATK – which had itself been formed by the merger of Orbital Sciences and Alliant Techsystems three years earlier. The former Orbital ATK operated as Northrop Grumman Innovation Systems until the start of 2020, when the company was restructured, and space vehicle operations transferred to Northrop Grumman Space Systems.

    Rendering of Stratolaunch’s Roc aircraft carrying a trio of Pegasus launch vehicles – via Stratolaunch

    The Pegasus XL vehicle which will fly Sunday’s mission was one of two originally built for Paul Allen’s Stratolaunch project, which were to have been launched from that company’s giant Roc aircraft – built by Northrop Grumman’s Scaled Composites subsidiary – while it worked on a new, larger rocket.

    Following Allen’s death in 2018, Stratolaunch has refocused its near-term plans on hypersonic research and abandoned its plans to fly Pegasus. Northrop Grumman subsequently bought back the rocket hardware that they had produced for the project.

    The Space Force reportedly paid around $28.1 million for Northrop Grumman’s launch services on Sunday’s mission, around half of what NASA originally paid for the Pegasus launch of their ICON satellite which was deployed in 2019. The low price is almost certainly down to the spare rockets that Northrop Grumman had on hand and a desire to launch them rather than continue paying for their storage and upkeep.

    Although the agreement to launch Sunday’s mission on Pegasus was secured last July under the Orbital/Suborbital Program 4 (OSP-4) contract, as part of the rapid response aspect of the TacRL-2 mission, Northrop Grumman and the Space Force’s Space Launch Delta 30 (the former 30th Space Launch Wing) were given only three weeks notice to prepare for the launch when it was actually due.

    In this time, the company has had to take delivery of the satellite, encapsulate it within the rocket’s payload fairing and mate with the Pegasus, attach the rocket to the Stargazer carrier aircraft, and carry out all of the usual steps and checkouts that make up the launch campaign. These activities have taken place at Vandenberg Space Force Base in California.

    At around midnight local time on Sunday, Stargazer will take off from Vandenberg and begin a climb to the drop altitude, likely to be around 39,000 to 40,000 feet (about 12 kilometers). Once at altitude, Stargazer normally flies an oval “racetrack” pattern, with one side of the oval lined up with the launch corridor, allowing it to come back around for another attempt should an issue delay launch on the first attempt. The relatively short six-minute launch window for Sunday’s launch means that there will only be time for one attempt.

    While Stargazer gets into position, systems aboard Pegasus will undergo final testing and preparation for launch, including checkouts of the vehicle’s flight controls. In the event a problem is detected while it is still attached to Stargazer, the launch can be aborted and the rocket brought back to Vandenberg for investigation or repair. In the event of a delay, a backup launch opportunity is available on Monday.

    The drop zone for the TacRL-2 launch is over the Pacific Ocean, to the west of Vandenberg. The launch corridor runs to the south, lining up with a likely sun-synchronous orbit. When Stargazer is flying along this heading within the drop zone, if all systems remain go for launch, Pegasus will be released from the belly of Stargazer.

    For the first five seconds of free flight, the rocket will fall, unpowered, before its first stage engine ignites. For a Pegasus launch, T-0 is timed as the moment the rocket is dropped from the carrier aircraft.

    Controlled by the three fins at the rear of its first stage, Pegasus will pitch up to being its climb reaching its maximum angle of attack eleven seconds after ignition. The rocket will pass through Max-Q, the area of maximum dynamic pressure, about 30 seconds into the first stage burn. After this, the vehicle will then begin to reduce its angle of attack, building up more horizontal velocity.

    The first stage of Pegasus XL ignites during the launch of CYGNSS for NASA – via Orbital ATK

    The first stage is powered by an Orion 50S XL solid rocket motor. This is a variant of the Orion 50 that is both stretched and equipped with the Pegasus wing and aft control surfaces. By contrast, the second stage, an Orion 50 XL, has the same stretched motor but without the wing or tail. Instead, the second and third stages are guided using thrust-vectored engine nozzles and reaction control thrusters.

    Pegasus will fire its first stage for 68.6 seconds. After this burns out, a short coast will follow before first stage separation and second stage ignition occur in quick succession at about T+89 seconds.

    The second stage Orion 50 XL will fire for 69.4 seconds, raising the apogee – or highest point – of the rocket’s trajectory to roughly the altitude of the planned orbit. Pegasus will reach space during the second stage burn, with the payload fairing separating from the nose of the rocket about 121 seconds into the flight, once it is no longer needed to protect the satellite from Earth’s atmosphere.

    After the second stage burns out, Pegasus will enter a coast phase where the second and third stages will remain attached as the rocket ascends towards its apogee. The duration of this coast will depend largely on the altitude of the target orbit – which has not been disclosed – but on a typical launch the coast will last a little over seven minutes.

    Diagram of the Pegasus XL rocket – via Orbital Science Corporation

    At its conclusion, the spent second stage will be jettisoned and the third stage will ignite for a 68.5-second burn to inject itself and its payload into orbit. The third stage uses an Orion 38 motor for this purpose.

    Spacecraft separation will occur shortly after third stage burnout, completing the forty-fifth mission for Northrop Grumman’s Pegasus rocket.

    Following the TacRL-2 mission, Pegasus faces an uncertain future. A second Pegasus XL rocket that was produced for the Stratolaunch project still exists. It is likely that Northrop Grumman will offer this at a reduced price to attract a customer – it is also possible that it could already be assigned to a similar mission to Sunday’s launch which has not yet been announced.

    In 2016, prior to its merger with Northrop Grumman, Orbital ATK indicated that they planned to continue offering the rocket with additional vehicles being manufactured if the need arose. Keeping the production lines open is unlikely to be a major problem for Northrop Grumman, due to the commonality with its other rockets.

    For most of its career, Pegasus has occupied a niche in the market. Because it is air-launched, it needs very little ground infrastructure once the rocket has been attached to the carrier aircraft, and integration can take place at Vandenberg before a ferry flight to another airstrip. This means that launches can take place from multiple sites around the world, targeting any orbital inclination.

    Virgin Orbit’s LauncherOne begins a successful launch to orbit in January 2021 – via Virgin Orbit

    As well as from Vandenberg, past Pegasus launches have taken place from Edwards Air Force Base in California, the Cape Canaveral Air Force Station (now Space Force Station) and Kennedy Space Center in Florida, Wallops Island in Virginia, Kwajalein Atoll in the Marshall Islands and Gran Canaria in the Canaries. In January, Virgin Orbit’s LauncherOne rocket became only the second air-launched rocket to reach orbit, ending Pegasus’ monopoly on this capability.

    With increasing competition from new rockets in its weight class and also from larger rockets like SpaceX’s Falcon 9, fewer satellites are looking to Pegasus for their ride into orbit. This was exemplified by NASA’s decision in 2019 to award the launch contract for the IXPE satellite to SpaceX.

    IXPE had been designed with Pegasus in mind, with its planned equatorial orbit requiring a launch from Kwajalein. SpaceX bid a flight-proven Falcon 9 at a lower cost than a typical Pegasus mission, and although this will be tied to a launch from Florida, Falcon has enough reserve performance to reach equatorial orbit through a plane change burn.

    Sunday’s launch is the first of two in quick succession for Northrop Grumman, with the company also expected to carry out a Minotaur I mission from the Mid-Atlantic Regional Spaceport, on Wallops Island, Virginia, on Tuesday. That flight is expected to deploy a classified national security payload – potentially a technology demonstrator – as part of the NROL-111 mission for the National Reconnaissance Office.

    (Lead photo of Pegasus XL and Stargazer prior to the launch of ICON – via NASA)

    The post Pegasus XL rocket to carry out Tactically Responsive Launch demo for Space Force appeared first on

    Source : NASA More   

    What's Your Reaction?


    Next Article

    Astra CEO Chris Kemp previews Rocket 4.0, daily launches, and a smarter planet

    In December 2020, Astra launched Rocket 3.2 to space. The successor, Rocket 3.3, will make… The post Astra CEO Chris Kemp previews Rocket 4.0, daily launches, and a smarter planet appeared first on

    Astra CEO Chris Kemp previews Rocket 4.0, daily launches, and a smarter planet

    In December 2020, Astra launched Rocket 3.2 to space. The successor, Rocket 3.3, will make Astra’s first flight with a payload on board as early as this summer. And by the end of the year, the Rocket 3 series is planned to launch on a monthly basis.

    In 2022, Astra is planning to debut Rocket 4.0 in order to launch missions weekly. CEO Chris Kemp spoke about these steps and the ones that will follow, including daily launches from around the world, during a recent episode of NASASpaceflight Live.

    Early Astra rockets

    In July 2018, Astra launched their first rocket, Rocket 1.0, on a suborbital test flight from the Pacific Spaceport Complex in Kodiak, Alaska, the same site that would host the entirety of Astra’s early test flight program.

    “We flew the first rocket with a suborbital license just about a year after we started the business,” told Kemp. “And these iterations were never intended to make it to orbit. In fact, they couldn’t make it to orbit. The upper stage of that first rocket was a hunk of metal. And we accepted each of these steps because we would learn a lot about, for example in that case, the first stage. And with each of these steps, the team got just a tremendous amount of data.”

    This iterative approach to research and development was integral to Astra’s plan to quickly achieve an orbital launch capability.

    “You’re seeing this same approach now being applied with the Starship program. This isn’t how SpaceX did it the first time, but it is definitely the best way to do it. And we applaud how they’re iterating and how they’re making these generations of spacecraft faster and better. And this is exactly what we’re doing.”

    Rocket 1.0 lifts off from the Pacific Spaceport Complex in Kodiak, Alaska – via Astra

    Astra launched Rocket 2.0, another suborbital test flight, just four months later in November 2018.  This was the final flight before the debut of the currently active Rocket 3 series, which incorporated several upgrades and changes from Rockets 1.0 and 2.0.

    “The first rocket we did, 1.0, the nosecone cost almost a quarter of a million dollars because it was made out of carbon fiber. Much like the Rocket Lab rockets. We actually want the entire rocket to cost less than that in the end. So you can’t make the nosecone cost a quarter of a million dollars or even anywhere near that and get to the ultimate price target.”

    “With the Rocket 2 series and 3 series, there were two different generations of the nosecones. And if you study the nosecone carefully, you’ll see the shape changes a little bit. And the price is now down around $25,000. So we’ve brought an order of magnitude cost out by using a really innovative aluminum and internal structure made out of aluminum tubes.”

    In addition to fairing upgrades, the rockets also got bigger. “Between Rocket 1.0 and the Rocket 3 series, we got feedback from the market that we needed to put more payload in space. And with constellations like Kuiper, with the Starlink constellation being deployed, with OneWeb and several other constellations, we really wanted to address that entire market. And so we realized the rocket needed to be a bit bigger to put these communications satellites up. And so we increased the diameter of the rocket from 38 to 52 inches.”

    Rocket 3 series

    Rocket 3.0 was set to make a launch attempt with customer payloads on board as part of the DARPA (Defense Advanced Research Projects Agency) launch challenge, which sought a launch provider to conduct two orbital launches from different launch sites within just days of each other. On the final day of the launch window, Astra reached the terminal countdown, but a sensor issue caused an abort, and the DARPA launch challenge prize went unclaimed.

    Rocket 3.0 is raised vertical ahead of Astra’s DARPA Launch Challenge attempt – via DARPA

    “In the actual DARPA Challenge, we got to T-52 seconds. We were in terminal count. And what actually prevented us from launching, I was very proud of the team, because it was sensor input that we got. And it was probably as one of the tanks was pressurizing.”

    Kemp explained that noises from the pressurizing tanks were at a frequency which caused an on board accelerometer to reset. “And it was super-interesting, because the entire XYZ didn’t reset, just one of the axes reset. Which was actually an undocumented feature in the sensor that we were using.”

    “And if that had happened in a flight, it could have given our guidance computer data that could have caused really, the consequences of that could be very difficult to predict. And you don’t want a rocket, as it’s lifting off, to have a guidance computer that doesn’t know what direction the thing’s pointed, even for a couple of milliseconds. So we decided the safe thing to do would be to not conduct the launch until we fully reviewed the cause of that issue.”

    After the DARPA challenge window closed, the payloads were removed, and Rocket 3.0 reverted to a test flight status. But before another launch attempt could be made, the vehicle exploded on the launch pad in March 2020.

    Keeping with the iterative development approach, Astra quickly moved to Rocket 3.1. “We brought one out for the DARPA Challenge, almost launched it. Blew it up by accident. Launched the next one. Launched the next one.”

    Rocket 3.1 was the first Rocket 3 series vehicle to fly, lifting off in September 2020. “We were able to quickly build another launcher, which reinforced the idea that this portable launch system was a great strategy. Because we could go back, put it all in containers, rebuild, send it back up there, and then launch again six months later.”

    Rocket 3.1 lifts off – via Astra/John Kraus

    This flight was terminated via a commanded engine shutdown approximately 30 seconds after liftoff. “We had another really complex issue with guidance, where the software system had the rocket clocked in a slightly different configuration. And it was going to fly off course, so we had to turn it off. And so the safety system just turned the engines off and the thing fell out of the sky after about 30 seconds.”

    “All the data other than that was perfect. And so we had one line of code in the guidance system that needed to be fixed, but as we scoured all the other data, the engines performed great. The pressurization system performed great. Terminal count performed great.”

    And so the teams moved on to Rocket 3.2. While the goal was to make progress towards reaching orbit, the teams were not afraid of falling short, so long as meaningful data was collected to improve the system for the next attempt.

    “We didn’t expect that flight to really reach space, and we didn’t expect the upper stage to perform as well as it did because it wasn’t tested and qualified to. I mean, we were really just trying to get the first stage working.”

    “When the upper stage lit, and the upper stage flew away, and the guidance system worked beautifully, and we made it to space, we passed the Von Karman line, we kept going, we kept going, we kept going.”

    “I’ve never seen more people see the point in their career and the point in their life where they’ve achieved something so incredible that, it was absolutely awe-inspiring.”

    In the end, the flight fell short of achieving orbit due to a fuel mixture issue on the rocket’s second stage. Kemp explained that, had Astra targeted a different orbit requiring a little less performance, the vehicle could have achieved orbit.

    “And certainly it could have achieved the orbit that we had targeted if we didn’t have 9% residual liquid oxygen on the upper stage.”

    Astra has since achieved a “near perfect” liquid oxygen and kerosene depletion on a full duration burn at their California factory and testing facility.

    Now, Astra is preparing to reach orbit for the first time with Rocket 3.3. In addition to correcting the fuel mixture problem, Astra has again increased the size of the rocket and will be placing customer payloads on board.

    Astra Updates
  • Commercial Space Forum Section
  • L2 Future Vehicles Section
  • Click here to Join L2
  • “Between Rocket 3.2, which flew a few months ago, and Rocket 3.3, we’ve increased its length by five feet. Because additional efficiencies in the engines mean that we can actually burn more fuel. And so because the diameter was already large enough, we could simply extend its length.”

    Following the Rocket 3.3 launch, the “launcher,” referring to the launch mount and erector on the ground, will remain in Kodiak to support more flights while Astra will send another launcher to a new site to support missions beginning later this year.

    “We were actually only planning on making about eight of these rockets. So we’ve increased the production run for the Rocket 3 series to a dozen. And we’ll be flying those monthly starting in the fourth quarter. And then that monthly rate will ramp up to weekly with the Rocket 4 series starting next year.”

    Setting Astra apart from competition

    Kemp described how he sees Astra’s role as a smallsat launch provider compared to other small offerings as well as large rockets.

    Astra’s factory – via Astra

    “I think there are some just fantastic companies out there that are building massive rockets that will have the ability take large amounts of cargo up into space. These are very large rockets, getting larger in a lot of cases. And we think that’s a critical piece of infrastructure when you’re going to Mars, putting large amounts of things in one place in space.”

    “But what we’re seeing is, we’re seeing hundreds of companies that have all formed over the past five, ten years. They all have different satellites. They’re all very small. They all want to go to different places in space, typically from different places on Earth, all on different schedules.”

    “So you can think of Astra of just filling in that gap in the market where we can access anywhere in space, on any schedule, from anywhere on Earth.”

    In order to make this offering at low cost, Kemp says reusability will not play a part at Astra. “The way to optimize the economics of a high-volume, low-cost system like the one that we’re building is to not attempt to reuse the system.”

    “If it costs millions of dollars to make the rocket, you totally want to reuse it, and so I can see why companies like Rocket Lab — when they have a Ferrari, carbon fiber, expensive thing — totally don’t want to throw that away. So I see why they’re going down that path. But for Astra, where our target is to make the entire rocket for a couple hundred thousand dollars, it just doesn’t make any sense for us.”

    Rocket Lab’s Electron first stage is recovered following the Return to Sender mission. Kemp says that Astra will differ from Rocket Lab in that they will not develop a reusable rocket – via Rocket Lab

    In addition to Rocket Lab, which was the first of a new wave of commercial small launch providers to achieve orbit, Kemp compared Astra’s costs to that of Virgin Orbit, which achieved orbit for the first time in January 2021.

    “How do we go and operate a system globally from as many spaceports as possible? How do we manufacture, some day, thousands of rockets a year and truly democratize access to space? And so who’s competing with us on that front? It’s not clear. We have Virgin Orbit, with a vehicle that they sell for $12 million. That’s three times more expensive. Carbon fiber. You need to deploy a 747 every time you fly it. With twelve shipping containers behind it. That’s our competitor.”

    Astra recently won a launch contract from NASA for the TROPICS mission, in which Astra beat not only Rocket Lab and Virgin Orbit, but also SpaceX’s Starship system. Kemp says the team was both surprised and humbled to be competing, and winning, against Starship.

    The post Astra CEO Chris Kemp previews Rocket 4.0, daily launches, and a smarter planet appeared first on

    Source : NASA More   

    This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies.