Fresh astro-underwear, anyone? Orbital shenanigans as Progress freighter has last-minute ISS docking wobble
- Reference: 1595594348
- News link: https://www.theregister.co.uk/2020/07/24/progress_iss_misalignment/
- Source link:
Those watching the video stream of the cargo ship docking with the International Space Station (ISS) were treated to the sight of the spacecraft seeming to go off course as it approached the outpost. With metres to go, Progress MS-15 [3]looked somewhat misaligned with the docking port on the Pirs module. Those onboard the orbiting lab suggested that maybe it might be time to take over manual control.
Russia: The hole in the ISS Soyuz lifeboat – was it the crew wot dunnit? [4]READ MORE
The spacecraft appeared to correct the alignment and the automated docking proceeded as planned. For watchers of the video stream, it all seemed a tad off-nominal.
NASA [5]made no mention of the wobble as it welcomed the arrival of the Progress and its cargo of almost three tons of food, fuel and supplies to the ISS. The docking took place at 17:45 UTC on 23 July just over three hours after a successful launch from the Baikonur Cosmodrome in Kazakhstan.
Unlike JAXA's HTV or SpaceX's first-generation Dragon cargo spacecraft, which require grappling by the ISS's robot arm, the Progress freighter is equipped with a Kurs-NA automated docking system. The original Kurs system saw use back in the days of Mir and a test involving the Russian TORU backup system resulted in a Progress freighter colliding with the Russian space station.
TORU, a manual docking system, has been used successfully in many other docking attempts since, including several with the ISS. Cosmonauts tend to fall back to it when the Kurs system has problems. In this instance, doubtless with an eye on the looming Progress, cosmonaut Anatoly Ivanishin suggested that perhaps now would be a good moment to take over, but was instructed by controllers to allow the automated docking to proceed.
Progress MS-15 (or 76) will remain at the ISS until December before being disposed of in the Earth's atmosphere. ®
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[1] https://www.spacecom.mil/MEDIA/NEWS-ARTICLES/Article/2285098/russia-conducts-space-based-anti-satellite-weapons-test/
[2] https://www.theregister.com/2020/07/24/russian_attack_satellite_allegation/
[3] http://russianspaceweb.com/progress-ms-15.html
[4] https://www.theregister.com/2018/09/14/hole_in_soyuz_caused_by_crew_says_russian_media/
[5] https://blogs.nasa.gov/spacestation/2020/07/23/resupply-ship-docks-to-station-after-two-orbits/
[6] https://whitepapers.theregister.com/
Re: Only 3 hours?
I'm not even sure if Kennedy Space Center has ever launched something going west, over central Florida. Maybe you could have done that in the 60s, but nowadays you have a major urban area at Orlando that you definitely would not want to drop space junk on.
I don't know about whether they take a lot of civilian payloads, but westbound military launches go out of Vandenberg AFB on the California coast, so you can shoot them out over the ocean.
Re: Only 3 hours?
Marketing Hack,
Are you sure that dropping an exploding rocket on Orlando wouldn’t be an improvement?
Re: Only 3 hours?
Launching towards the east gets you a boost from the earth's rotation. The closer to the equator the better.
Re: Only 3 hours?
The SpaceX crew Dragon deliberately went on a slow journey so the systems and habitability could be properly tested, in fact after the first launch attempt was aborted for weather the next opportunity was skipped because the flight would have been too short. Future Dragons may well take a quicker route if the timings are right.
All launches to the ISS from whatever launch site are timed to go up as the ground track of the ISS orbit passes over the launch site, but the ISS can be at any point along the orbit. This means the station and craft land up in the same plane but have to wait until the Soyuz/Dragon/Cygnus/Whatever catches up before they can dock. The different rockets can cope with different amounts of off ideal timing by doing a small (it costs fuel and payload) dogleg manouevre, and the latitude of Baikanour means the ground track gives a lot more flexibility in exact launch times when combined with the Soyuz capabilities. The Russians are thus able to pick launch times and dates to minimise the flight time, NASA and JAXA could pick launch dates that would give a 2 orbit 3 hour trip, but that would drastically reduce the number of possible launch windows.
Re: Only 3 hours?
Most space launches go to the east, so that the rotation of the Earth contributes to the velocity required to get into orbit. Launching to the west would require a lot more fuel to get to the same altitude.
As to why the different journey times, I would guess it really depends on the timing of the launch:
AIUI the ISS isn't in an equatorial orbit, but is skewed by about 50°, I believe as a compromise to make it easier for Russian launches to reach it. As a consequence of this, and it being in low orbit, the places its path crosses changes from one orbit to the next. Sometimes the station will be in a convenient place when your payload reaches orbit, sometimes you have to manoeuvre and wait for the orbits to sync up.
Re: Only 3 hours?
They fly up the west coast, because the boost from the rotation sin't nearly as important as getting the inclination right to start with
More Bondo, Number One!
"Those watching the video stream of the cargo ship docking with the International Space Station (ISS) were treated to the sight of the spacecraft seeming to go off course as it approached the outpost."
"RAMMING SPEED!"
Don't worry, that software bug is totally correctable.
Contactless Delivery Service Possibly?
If my favorite pizza restaurant can institute contactless delivery, and call it progress, why shouldn't the Russian freighter do the same, particularly since its name is "Progress". The automated docking system was just trying to follow the latest coronavirus recommendations, until everyone started complaining.
Re: Contactless Delivery Service Possibly?
Perhaps it’s using the new Amazon software? And it was going to throw the payload over the garden fence and chuck a card through the airlock saying, "We rang and you were out."
Only 3 hours?
I guess it's down to the Russian rockets launching from Baikonur but it seems very strange that they only take 3 hours to reach the ISS and yet SpaceX takes much longer (about 19 hours - eg: Crew Demo 2 launched on 30 May 2020 at 19:22:45 UTC and soft docked at 14:16 UTC on 31 May 2020.
Baikonur is at 45.965°N 63.305°E and yet Kennedy is at 28°31′27″N 80°39′03″W.
Maybe it's down to the fact that rockets leaving Kennedy are normally launched towards the East over the Atlantic on a "just in case" basis? (and not "initially" flying over built up areas).
Can someone else can elucidate?