Update from ESA's Thomas Beck at ATV-CC on today's reboost, the last planned reboost of the ATV-4 mission.
At 13:03 CEST, ATV-4 used two of its main engines, OCS1 and OCS3, to lift the ISS into a higher orbit. After a burn of 256.6 secs, the velocity of the orbital complex was changed by 0.62 m/sec. The manoeuvre burned 86.0kg of propellant.
This was the last scheduled reboost of ATV-4, which is set to undock from the ISS on Monday, 28 October 2013.
ATV-4 set to lift the Station tomorrow
Details on tomorrow's planned reboost for the ISS – the final one in the ATV-4 mission – from ESA's Thomas Beck at ATV-CC.
The reboost on Thursday [24.10] is planned to generate a modest delta-V (change in speed) of about 0.6 m/sec and to use approximately 85 kg of fuel.
The corresponding small increase in ISS altitude should be on the order of a bit less than 2 kilometres. The back-up date for this reboost is Saturday, 26 October.
I will provide more up-to-date figures after reboost termination.
Update sent in last night from ESA's Mission Director Thomas Beck, at ATV-CC:
Today's reboost of the ISS was successful. At 19:35 GMT (21:35 CEST), ATV Albert Einstein used its two main engines (OCS1 and OCS3) to lift the ISS into a higher orbit. After a burn of 815 secs, the velocity of the orbital complex was increased by 1.95 m/sec. The amount of propellant burned for this manoeuvre was 271.6 kg.
The next reboost is planned for 23 October 2013, the final planned boost before ATV-4 departure from the ISS.
ATV-4 mission report 13 September
After the Station reboost on 15 September, it's been relatively quiet for ATV. Next up: 19 September - Air transfer to the ISS and 2 October - Reboost.
ATV-CC 15 June 2013 Credit: ESA
Note as always: All dates/timings below are forecast only and are subject to change as this is a continuing, dynamic mission. Time below indicated in UTC.
On Sunday, 15 September, ATV-4 conducted a reboost for the ISS. Starting at 14:42 CEST, ATV Albert Einstein used two of its four main engines (OCS1 & OCS3) to lift the ISS into a slightly higher orbit.
After a burn of 205 secs, the velocity of the orbital complex was increased by 0.50 m/sec. The amount of propellant burned for this manoeuvre was 68.1 kg.
The next reboost using ATV is planned for 2 October 2013.
Thanks, Thomas Beck, at ATV-CC for the update!
Today’s ISS reboost complete
Update from ESA Mission Director Thomas Beck at ATV-CC:
At 09:20 CEST today, ATV-4 used two of its four main engines (M1 and M3) to lift the ISS into a slightly higher orbit. After a burn of 185 secs, the velocity of the orbital complex has been increased by 0.48 m/sec. The amount of propellant burned for this manoeuvre was 68.68 kg.
The next reboost using ATV is planned for 13 September 2013.
Regards -- Thomas
ATV-4′s first ISS reboost complete
Quick update from ESA Mission Director Thomas Beck at ATV-CC Toulouse:
Today's ISS reboost by ATV-4 was successfully completed just before 07:45 CEST. The firing of Albert Einstein's Orbital Control System (OCS) engines No. 2 and 4 started at 07:35 CEST, lasted slightly less than 10 minutes and resulted in a 'delta-v' (change in Station velocity) of 1.45 m/sec. The manoeuvre consumed 199 kg of propellant.
ATV conducts first reboost for the International Space Station
A brief update from ESA's Thomas Beck, Mission Director responsible for reboost operations at ATV-CC.
The first reboost of the of the ISS by ATV-4 has just finished and was fully successful. Two OCS (orbital control system) thrusters (engines 2, 4) functioned flawlessly during the burn that started at 15:05 CEST and lasted 407 sec. ATV provided the ISS with a change in velocity (delta-v) of 1.0 m/sec.
The next propulsive support, using just the ACS system (attitude control system, i.e. thrusters) is planned during the EVA next week (24 June) during which ATV's propulsion system will be used to 'desaturate' the ISS control momentum gyroscope (CMG).
Desaturation means, essentially, that ATV takes over attitude control for the ISS while the the gyroscope wheels are off-loaded.
Assume the ISS has an acceleration of 0.03 m/s2 (this is the acceleration just due to the ATV reboost, not the gravitational acceleration). If an astronaut started in the Destiny module and let go, how long would it take to “fall” [as the astros are seen doing in the YT video] all the way to the back. You might want to look up this distance, but I think it is around 50 meters.
Interested? We'd like to invite all our ATV blog readers to answer any one (or all!) of Dr Allain's 'ATV Homework Questions'. Send us your answers, and we'll publish the best (or, at least, correct) ones as assessed by the ATV Operations team. The answer judged most imaginative will win a super ATV prize from our mission goody closet. Submit your own work only, please. All judging final. No cash value. One submission per entrant. Due date Friday, 3 May, 12:00 CEST.
Astronaut selection requires three fundamental tenets: health, brains, and experience. You have to be able to pass the toughest medical in the world, so stay in shape and eat right. You have to demonstrate the ability to learn complex things, so an advanced technical degree is needed. And you have to demonstrate good decision-making when the consequences really matter.
Using astronaut Mike Fossum’s YouTube video to measure ATV acceleration
By Rhett Allain
The Automated Transfer Vehicle (ATV) doesn’t just bring supplies to the International Space Station. It can also be used for ISS reboosts. What is a reboost? In short, during a reboost, the ISS velocity is increased by a small amount to bring the space station up to a slightly higher orbit.
Why is this needed? Well, although the ISS is in space, there is still stuff up there (gas from the atmosphere) that exerts a small drag force on the Station, decreases its velocity. The reboost are there just to keep it where it needs to be.
This video shows the inside of the ISS during an ATV reboost, i.e. when the ATV's main thrusters were firing. Let’s see if we can estimate the ATV thrust based on the acceleration of astronauts inside the space station.
Editor's note: In addition to having a knack for science communication, Rhett Allain is Associate Professor of Physics at Southeastern Louisiana University. He writes regularly for Wired's Dot Physics blog and is a bit of a physics fanatic who spends more time than many pondering how daily life intersects with science. With the recently announced development of ATV in cooperation with NASA for Orion, we're delighted to feature a few posts from the far side of the Atlantic. Enjoy! – DGS
There are a couple of different ways you can measure the acceleration in NASA astronaut Mike Fossum's YouTube video, but I am going to use one of the astronauts themselves (we think this is the first scientific use of an astronaut's floating body as seen in a YT video to calculate ATV acceleration – Ed).
Basically, I will use a video analysis program (in this case, the free Tracker Video Analysis). With video analysis, you can get position and time data from each frame of a video. If the motion of the astronauts had been recorded from a side view, position vs. time would obviously be the best choice. As you can see in Mike's video above, however, Mike, astro Satoshi Furukawa and cosmonaut Sergy Volkov are moving away from the camera, so I will measure the angular size of a person.
As things move farther away from a camera, they also appear steadily smaller. Here is a diagram that shows the relationship between angle, size and distance.
If you know the angle theta (θ) and the length of the object, you can find the distance (which I call r) with the formula:
r = L / θ
With this, I can mark a point on each side of one of the receding astronauts as he accelerates away from the camera. With some basic estimations for the angular view of the camera (and size of an astronaut), I get the following plot of distance from the camera for one of the astronauts.
Times in UTC
6/05 - ATV-4 moves to the BAF for final preparations
8/05 - ESA Operations Readiness Review
20/05 - Late-cargo loading
31/05 - Launch Readiness Review
03/06 - IMMT GO/NO-GO for launch & docking
05/06 - Lift-off Arianespace VA213 23:52 CEST
15/06 - Docking 15:46 CEST
28/10 - Undocking 9:55 CET
2/11 - Reentry 13:05 CET All future dates subject to change