Starship SN5 set for a static fire followed shortly by a 150-meter hop attempt

Starship SN5 is finally set to begin Raptor engine testing this weekend after a successful… The post Starship SN5 set for a static fire followed shortly by a 150-meter hop attempt appeared first on

Starship SN5 set for a static fire followed shortly by a 150-meter hop attempt

Starship SN5 is finally set to begin Raptor engine testing this weekend after a successful cryogenic proof test on July 1. If the static fire test is successful, it will clear the way for a 150-meter hop test as early as next week. The 150-meter hop will be the first test flight of a full-scale Starship tank section.

A successful cryogenic proof test on July 1 verified that Starship SN5 can withstand the forces associated with engine testing. These forces include the pressure created by the cryogenic propellants and the thrust from the Raptor engine.

Ahead of the static fire test, the hydraulic thrust simulator – used for the proof testing – was removed to make way for a Raptor engine. Raptor SN27 is the engine chosen for use on SN5.

A gap of over two weeks between the cryogenic proof test and a static fire of SN5 was longer than expected – based on how quickly SN4 moved into engine testing. Two primary factors are a result of this gap.

The first is that numerous upgrades to the ground support equipment have been made since Starship SN4 exploded at the launch pad. Thus, it has taken time to work out all of the kinks.

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  • The second and largest reason is that unlike Starship SN4, SN5 is being prepped for a flight test right out of the gate. SpaceX does not plan to perform an extended ground test campaign with SN5 after beginning Raptor engine testing.

    It is understood that one good static fire test could be enough to clear the way for a 150-meter hop test. Furthermore, only a few days may be required to prepare SN5 for the flight test following a successful static fire test. If a static fire occurs this weekend, this will put the earliest possible hop date in the first half of next week.

    It should also be noted, however, that Starship testing schedules and plans are extremely fluid. Plans may change, and multiple static fires or other ground tests will be conducted before the hop.

    During the upcoming static fire test, Starship SN5 will fire its single Raptor engine for a few seconds. This test will allow SpaceX to verify that the Raptor engine is properly functioning on the vehicle ahead of the flight.

    The test will also help verify that the ground support equipment is functioning properly. While it is easy to focus on the Starship vehicle itself, the ground support equipment is also highly complex and must function properly for testing to be successful.

    If minor issues crop up during the countdown for a static fire test, SpaceX will have the option to either abort the test and try again later or to instead settle for a spin prime or preburner test.

    A spin prime test is where propellent is purged through the Raptor engine without being ignited, and a preburner test fires up the engine turbopumps without igniting the main combustion chamber.

    Once a successful static fire test is conducted, SpaceX teams will take a few days to perform data review, inspections, and decide if the vehicle is “go” for a hop attempt.

    The only vehicle that has previously flown from SpaceX’s Boca Chica launch facility in South Texas is Starhopper. Starhopper was a smaller prototype compared to the full-scale Starship tank section that is Starship SN5.

    SpaceX’s “Starhopper” test vehicle performing a 150m test flight at their Boca Chica, Texas facility. Credit: SpaceX

    Starship SN5’s flight will be similar in profile to Starhopper’s final flight which targeted 150-meters in altitude. SN5 will also land on the same landing pad which is located adjacent to the launch pad.

    However, Starship SN5 will also have to deploy landing legs. The vehicle has six landing legs located inside of its thrust section. Starhopper on the other hand had three landing legs that were permanently fixed to the exterior of the vehicle.

    If the 150-meter flight of Starship SN5 is successful, SpaceX is expected to quickly move on to Starship SN8 for the next flight test – skipping the SN6 prototype.

    It remains unclear if Starship SN6 would still go to the launch site for ground testing or if it would be scrapped following a successful flight of SN5.

    Another uncertainty is if SpaceX would use SN6 for another attempt at the 150-meter hop test, if SN5 were to be unsuccessful in its attempt.

    Whatever the case, SpaceX teams are understood to be eager to get Starship SN8 completed. The vehicle will feature major upgrades over previous Starship prototypes. SN8 will be built out of 304L stainless steel versus 301, receive a fairing, aerosurfaces, and three Raptor engines to allow for a higher altitude test flight.

    Like all testing plans in Boca Chica, there is a chance that these plans for SN8 will change, but they are understood to represent the current thinking.

    The fairing for a Starship prototype is stacked in Boca Chica, Texas. Credit: BocaChicaGal for NSF

    A fairing section was stacked Tuesday at the Boca Chica production site and is potentially the fairing that will be used for SN8.

    Meanwhile, SpaceX is also preparing another test tank to be proof tested to destruction. The most recent test tank, designated SN7, achieved a record pressure before it failed. SN7 was the pathfinder vehicle for the switch to 304L stainless steel.

    The next test tank – designated SN7.1 – will feature further build-quality improvements, as it attempts to break the record set by SN7.

    The test tanks are used to inform the design and build process for the full-scale Starship vehicles.

    *Subscribe to the NSF Youtube channel for 100s of exclusive Starship Videos*

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    Northrop Grumman set to launch NROL-129 from MARS

    Northrop Grumman stands ready to launch the classified NROL-129 mission, consisting of four payloads designed… The post Northrop Grumman set to launch NROL-129 from MARS appeared first on

    Northrop Grumman set to launch NROL-129 from MARS

    Northrop Grumman stands ready to launch the classified NROL-129 mission, consisting of four payloads designed and built by the National Reconnaissance Office.  Liftoff is targeted for Wednesday, 15 July in a launch window that opens at 09:00 EDT (13:00 UTC).

    This will be the first launch of the Minotaur IV from the Mid-Atlantic Regional Spaceport (MARS) at NASA’s Wallops Flight Facility, which is located on the eastern shore of Virginia near the town of Wattsville.

    Preparations for launch began in earnest more than a month and a half ago, as teams from Northrop Grumman and the National Reconnaissance Office (NRO) took possession of various elements for the flight, including all of the solid propellant motor segments which were delivered and stacked in June.

    Payload encapsulation and final processing occurred at the new payload processing facility built on Wallops island, something which greatly streamlined pre-launch operation and integration flows for the classified NROL-129 payloads and their Minotaur IV carrier rocket. 

    After completing all pre-flight activities, including a joint Mission Dress Rehearsal on Friday, 10 July, Northrop Grumman entered final closeout operations for the rocket over the weekend. 

    For launch, teams came on console in the early morning hours and started the countdown at 04:00 EDT (08:00 UTC).

    “You know on a solid rocket motor vehicle that launches from the ground, it’s a fairly straightforward countdown,” said Kurt Eberly, Program Director, Small and Medium Space Launch for Northrop Grumman, in a one-on-one interview with NASASpaceflight.

    “We power up all the avionics.  We initialize all the computers and the different processors on each of the stages.  We do some wiggle tests of the Thrust Vector Controllers using ground power.  And then you know about an hour before launch, we start an initialization of the navigator, the inertial navigator.”

    “That’s a ring laser gyro assembly.  And so we start a gyro-compass algorithm that’s basically using gravity and the rotation of the Earth to go through an algorithm to basically initialize the position and instrument of the inertial navigation set.”

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  • During practice countdown and vehicle power ups for checkout operations, teams took careful note of how the inertial navigator powered up and how it was aligned.  “So we have those written down carefully,” said Mr. Eberly, “and we’ll compare the launch-day alignment to the prior alignment and make sure it’s within tolerance.”

    As always, though, all pre-launch activity won’t be confined to the ground.

    “Getting close to launch, there’s a bunch of range activity.  We’ll be flying balloons pretty much every hour to get a sense of the winds aloft.  And [then we’ll] do some evaluation of the wind profile on that day.”

    The Range Weather Officer will provide the wind profile that allows the Guidance, Navigation and Control teams to check that upper level winds and their associated shear are within safety limits for the Minotaur IV.

    After that, teams will remotely arm the ordnance on the Minotaur IV, which will be followed by turning on ordnance power.  A series of checkouts will then follow to clear Minotaur IV for launch.

    Minotaur IV on Pad-0B at MARS the day before its scheduled 15 July 2020 launch of NROL-129. (Credit: Northrop Grumman/Thom Baur)

    When the count reaches zero, Minotaur’s IV first stage will ignite on Pad-0B and the solid motor will reach full thrust within 0.2 seconds with liftoff following nearly instantaneously.

    “It’s a very rapid event compared to a liquid.  There is no spooling up of the turbopumps or anything like that.  You ignite it, and you are off and going.  And that’s just typical of a strategic missile.  It’s not hanging around for long,” said Mr. Eberly.

    Minotaur IV itself is a modified Peacekeeper intercontinental ballistic missile.  The first stage is an SR-118 solid motor that delivers 2,200 kN (490,000 lbf) thrust.

    The stage will then hand off to the SR-119 second stage, another solid motor that delivers 1,365 kN (307,000 lbf) thrust for 54 seconds.

    The third stage is an SR-120.  Delivering 329 kN (74,000 lbf) thrust and burning for 62 seconds, this will complete the first part of the ascent, after which the fourth stage will enter a prolonged coast to apogee.

    During the first three stages of flight, communication with the rocket will be routed through tracking stations in Bermuda and at Coquina, North Carolina. 

    However, the long coast up to apogee will place the fourth stage too far down range to communicate with those tracking stations when it ignites.  To solve that issue, the rocket will communicate upwards with NASA’s Tracking and Data Relay Satellite (TDRS) network in geostationary orbit.

    Due to the classified nature of the mission, no information is available on the exact time when the final stage will reach apogee and ignite the solid propellant Orion 38 motor.

    Regardless, thanks to precise mass measurements of the Orion 38, a precise knowledge of not just the propellant mixture but exactly how hot and fast that propellant mixture burns, and the exact mass of the four classified payloads will result in the Orion 38 inserting the mission into a very precise orbit despite being a solid rocket motor that must burn to depletion once ignited. 

    Confirmation of successful payload deployment and mission completion might come from Northrop Grumman or the NRO itself — or from orbital tracking information as is sometimes the case with classified missions.

    The next two NRO missions, NROL-44 and NROL-101, are slated to launch in August and September from Cape Canaveral Air Force Station, Florida, on United Launch Alliance’s Delta IV Heavy and Atlas V 531 rockets, respectively.

    (Lead image: Northrop Grumman/Thom Baur)

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