Europe and Russia launch Emirati military/civilian Earth imaging satellite

Arianespace has used — with Russia’s support — a Soyuz ST-A rocket to launch a… The post Europe and Russia launch Emirati military/civilian Earth imaging satellite appeared first on NASASpaceFlight.com.

Europe and Russia launch Emirati military/civilian Earth imaging satellite

Arianespace has used — with Russia’s support — a Soyuz ST-A rocket to launch a joint military and civilian Earth imaging satellite for the United Arab Emirates Armed Forces from the Guiana Space Centre near Kourou, French Guiana.

Liftoff of the Falcon Eye 2 satellite occurred at 20:33:28 EST on Tuesday, 1 December (01:33:28 UTC on Wednesday, 2 December) to ensure the satellite reaches the proper sun-synchronous orbit.

Launch is currently in a coast period before a final burn of the Fregat-M upper stage places Falcon Eye 2 into its final orbit 58 minutes after liftoff at 21:32:13 EST (02:32:13 UTC).

The mission was originally scheduled to launch on a Vega rocket, like its predecessor — Falcon Eye 1 — did in July 2019.  That mission ended abruptly 14 seconds after stage two ignition when the Vega rocket suffered the first of its two failures to-date.

Shortly after separation of the launcher’s first and second solid propellant stages, the forward dome on the Z23 motor (second stage) suffered a “thermo-structural failure” leading to a “violent event” that “led to a breakup of the launcher” — an engineering way of saying that the thermal protection system at the top of the Z23 stage failed, causing the destruction of the rocket and payload.

Following the failure, the United Arab Emirates (UAE) Armed Forces asked for Falcon Eye 2’s launch to be changed to a Soyuz rocket with a Fregat-M upper stage so as not to launch on Vega again and allow for a smoother and more timely launch not subject to Vega’s return timeline.

Launch was rescheduled for 20 February 2020 before moving to 5 March.  That day, teams found an issue with “one of the liquid propellant small thrust engines” on the Fregat-M upper stage of the Soyuz during day-of-launch checkouts.  Later reports indicated the issue was a leak of oxidizer.

Initially a “one day” delay, the issue quickly pushed the launch back to 10 April within hours of its discovery as the entire Fregat-M upper stage needed to be replaced — with the stage itself going back to Russia.

At first, Russia offered a software solution to the issue, but Arianespace, the UAE Armed Forces, and France (French organizations own slightly more than 64% of Arianespace) opted to replace the stage instead.

With COVID-19 cases growing, the French government initiated public health measures and lockdowns — with all non-essential work stopping throughout the country, including its overseas departments of which French Guiana is one.

With the space centre closed, the mission was delayed to a preliminary target of mid-September should COVID-19 restrictions allow.

On 30 May, an alarm at the storage site of the Fregat-M upper stage alerted personnel of a potential, and highly toxic, nitrogen tetroxide leak.  A team was dispatched from Russia; no word of whether the alarm was false or true was given.

Days later, the flight was pushed back to no earlier than 17 October.

By late-September, an additional issue with the Fregat-M upper stage was discovered and the launch postponed to 3 November, which itself was later moved back to the “end of November”.

A launch attempt for Saturday, 28 November local time was on track, with the Soyuz rolling to the pad on Tuesday, 24 November before a Launch Readiness Review cleared the mission for liftoff.

Soyuz lifts off from the Guiana Space Centre. (Credit: Arianespace)

That attempt was stopped hours before liftoff, with indications the delay was caused by weather.  Launch was quickly reset for Sunday, 29 November at exactly 20:33:28 EST.  That attempt was likewise scrubbed for weather — lightning — at T-7 minutes.

An attempt the following day was scrubbed just two minutes before liftoff when telemetry could not be properly received from the rocket at the launch site.

The Soyuz ST-A rocket is a baseline Soyuz 2.1a launcher that incorporates several European modifications — including but not limited to combustion chamber pyrotechnics, a European payload adaptor, and a European flight termination system.

A Blok-I stage (stage 3 to Arianespace) sits atop the central stage.  The Fregat-M upper stage and payload ride enclosed in the payload fairing.

The engine ignition sequence will begin at T-16 seconds, when European pyrotechnic charges will fire inside all 32 combustion chambers — 20 total for the five main engines plus 12 vernier (steering) engines that all have to be lit for liftoff.

After the ignition process begins, all 32 combustion chambers will reach preliminary thrust levels by T-14 seconds, at which point the critical process of confirming ignition inside every single chamber will occur.

Once confirmed, RP-1 kerosene propellant lines will be opened, resulting in full, safe combustion in all chambers beginning at T-4 seconds.  Full thrust will be reached at T-1 second.

At liftoff, the Soyuz ST-A will perform a pitch and roll program to align itself for a flight just west of due north.  This will place the payload into its intended sun-synchronous orbit.

Flight events are expected as follows: 

Time since liftoff (T+ ) Event
T+ 1 min 58 secs Booster separation (end of 1st stage)
T+ 3 mins 59 secs Payload fairing jettison
T+ 4 mins 45 secs 3rd stage “hot-fire” ignition
T+ 4 mins 47 secs 2nd/3rd stage separation
T+ 8 mins 44 secs 3rd stage shutdown
T+ 8 mins 48 secs 3rd stage separation
T+ 9 mins 49 secs Fregat-M burn #1 begins
T+ 17 mins 12 secs Fregat-M burn #1 complete
Initial parking orbit insertion
T+ 54 mins 51 secs Fregat-M burn #2 begins
T+ 55 mins 24 secs Fregat-M burn #2 complete
T+ 58 mins 45 secs Falcon Eye 2 separation
T+ 1 hr 50 mins 55 secs Fregat-M burn #3 begins
T+ 1 hr 51 mins 56 secs Fregat-M burn #3 complete
T+ 1 hr 58 mins 43 secs End of mission

Falcon Eye 2, will be released into a sun-synchronous orbit with a mean altitude of 611 km.  With a mass of 1,190 kg, the joint military-civilian Earth observation and reconnaissance satellite was originally designed to work in concert with Falcon Eye 1 and carries the same High-Resolution Imager system, capable of resolving objects of 70 cm across a 20 km field of view.

A network of ground stations will participate in initial commissioning of the satellite and serve as a downlink relay during its planned five year mission, which will be managed by Emirati operations.

The satellite will serve dual roles: providing support for the UAE Armed forces and obtaining commercial images for sale.

Based on newer generation Pléiades Earth imaging satellite from France, Falcon Eye 2 was built by Airbus Defence and Space and Thales Alenia Space.  Airbus Defence and Space handled overall satellite design while Thales Alenia Space provided the payload and optical instruments.

Lead image: A Soyuz on the launch pad at the Guiana Space Centre. Credit: Arianespace

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Source : NASA More   

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China lands on Moon after causing deep confusion by stopping broadcast

Eight days after launching from the Wenchang Spacecraft Launch Site in southern China, the nation’s… The post China lands on Moon after causing deep confusion by stopping broadcast appeared first on NASASpaceFlight.com.

China lands on Moon after causing deep confusion by stopping broadcast

Eight days after launching from the Wenchang Spacecraft Launch Site in southern China, the nation’s Chang’e 5 mission has landed at Mons Rümker on the Moon to collect approximately 2 kg of material for near-immediate return to Earth.

The Chang’e 5 lander began final descent at 09:58 EST (14:58 UTC) with an expected touchdown 15 minutes later at 10:13 EST (15:13 UTC).

All broadcasts of the event were abruptly stopped just before the landing burn was to begin — throwing the mission into question with CCTV in China at first saying landing coverage would resume at 21:00 EST — an 11 hour delay to the landing.  Minutes later, official sources — via social media — proclaimed a successful landing.

The supposed-to-be highly public landing on the lunar surface came after a successful launch on 23 November, which was followed by a Trans-Lunar Injection burn and then three trajectory course corrections on the 24th, 25th, and 27th. 

The first of two Lunar Orbit Insertion burns was successfully accomplished on 28 November at 13:06 UTC before a second on 29 November at 12:34 UTC circularized the orbit above the Moon’s surface.

This placed the combined Orbiter and Lander components in the correct orbit for spacecraft separation, which occurred successfully at 20:40 UTC on 29 November.

On 30 November, the Lander began a series of burns to lower its orbit to allow for a landing today at Mons Rümker.

The 15 minute descent to the lunar surface will be automated, with controllers back in China monitoring the progress of the Lander as it lowers itself toward the lunar surface.

While landing on another celestial body is difficult, China has a good track record for successfully getting probes to the Moon — with the nation’s previous four lunar missions all being successful, including two landings.

If all goes to plan, and Chang’e 5 successfully touches down on the Moon, it will begin its lunar surface operations just 2 hours after landing when it deploys its subsurface drill to begin breaking through the top layer of the lunar surface.

Drilling will allow the mission to obtain samples from 2 meters below the immediate lunar surface.

That drilling and subsurface collection operation (which will begin just 2 hours 2 minutes after touchdown), will continue for about 2.5 hours.

If that subsurface operation is successful, scooping of lunar surface material will then follow over a 22 hour period, beginning 11 hours after touchdown. 

Overall, about 2 kg of lunar material is expected to be scooped from both the surface and subsurface locations.

Under the original plan, the samples were to be secured inside of the Ascent Stage, which will then be configured for a launch from the lunar surface on 3 December 2020 at 15:10 UTC. 

After ascending into low lunar orbit, the Ascent Stage will deploy its solar arrays 17 minutes after liftoff before going on to perform a series of four phasing burns on the 3rd, 4th, and 5th of December before rendezvousing with the Orbiter on 5 December.

The Ascent Stage will then dock to the Orbiter on 5 December at 21:40 UTC.  After docking, the collected samples will be transferred to the return capsule just 21 minutes later.

European tracking stations for the Chang’e 5 mission. (Credit: ESA)

If the pre-mission timeline is followed, the Return Capsule will reenter Earth’s atmosphere for a landing in Dorbod Banner, Inner Mongolia, People’s Republic of China on 16 December, concluding the planned 23-day Chang’e 5 mission. 

During reentry, the European Maspalomas tracking station in the Canary Islands, Spain, will monitor the craft as it heads toward Mongolia.  European tracking stations will also monitor the descent to and landing on the Moon today using a tracking station at the Guiana Space Centre near Kourou, French Guiana.

If the samples are returned safely, it will mark the first time China will have accomplished a lunar sample return, with China becoming only the third nation to do so (the others being the Soviet Union and the United States).

It will also mark the first time since the Luna 24 mission of the Soviet Union in 1976 that lunar material has been returned to Earth.

The Chang’e lander, meanwhile, will be left on the surface of the Moon and continue to function through the remaining 10-ish days of daylight at Mons Rümker.

Unlike Chang’e 4, which was equipped to survive the lunar night, Chang’e 5 does not carry that equipment, and the lander will cease operation shortly after nightfall at its landing site.

This compressed timeline is why the sample collection process will begin so quickly after landing — so that if any issues present, control teams in China can troubleshoot and attempt to recover over the immediately following days.

Lead image: Chang’e 5 animation. Credit: CNSA

The post China lands on Moon after causing deep confusion by stopping broadcast appeared first on NASASpaceFlight.com.

Source : NASA More   

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