The Incredible European ATV

[PJay_A]

I just realized how valuable an asset ESA's ATV is to the space station program! Besides acting as a larger version of the Russian Progress cargo ship, the increased fuel it carries allows it to give the station vital orbital reboosts much more so than the Progress; and with the shuttle fleet retiring, it and the Progress will be the only vehicles with the capability to do this function as Japan's HTV and commercial cargo ships which are currently being developed do not have such capabilities. In addition, the ATV's large interior pressurized volume makes it comparable to a permanent module during each vehicle's 6-month stay at the station.

Knowing all that, would it be wise for NASA to buy or barter for an increased frequency of ATV visits from 1 a year to 2 a year or 2 every 9 months? The incredible reboots capability of this vehicle is worth it alone in light of shuttle's retirement!

Anyone know what the ISS's current altitude is and how we can see it on a graph over time?

Also, if Congress grants approval for STS-135, the cost would cover another year for shuttle personnel employment. If we extend their employment, it wouldn't be a stretch to add an additional flight for the other two orbiters. I believe there's leftover hardware to support another 2 or 3 flights. I say if we can justify another mission for each orbiter, let's do it! We could, for example, send Node 4 up, maybe the Centrifuge Accomidation Module if we can rehabilitate it, and convert at least another MMLP into another PLM.

One last question: Does anyone know what altitude they're planning on raising ISS after the shuttle's retire?

 

[PJay_A]

I forgot to mention that if ESA goes through with a proposal to upgrade the ATV to allow it to parachute back and return to Earth with cargo, it is not a stretch to modify it even further to allow it to return people (planned return or emergency escape return). This would further justify having one attached (2 a year) at all time!

 

[Gravity_Ray]

The ATV is an amazing machine.

Its size gives it certain abilities that cannot be matched by any ship except the space shuttle. I doubt the ISS will need more than 1 of these a year. I don’t know that there is that much stuff to go up there once the shuttle retires. As a matter of fact I think that it’s not so much the up mass that is critical for space science on the ISS, but the down mass.

I am looking forward to the day that the ATV can be man rated. I think it is going in that direction.

By the way here is a graph of the ISS altitude. I don’t think the ISS altitude is going to be raised too much as it depends on the Earth’s atmosphere to protect the astronauts on board.

http://en.wikipedia.org/wiki/File:Internationale_Raumstation_Bahnhöhe_(dumb_version).png


I am hoping that the ISS won’t need the Russians and the ATV to re-boost after much time. I am hoping that they put a VASIMR engine on the ISS for all the re-boosting. That will be a great experiment. Certainly it will be cheaper.

 

[EarthlingX]

Anyone know what the ISS's current altitude is and how we can see it on a graph over time?

http://www.heavens-above.com : ISS Height Profile

This plot shows the orbital height of the ISS over the last year. Clearly visible are the re-boosts which suddenly increase the height, and the gradual decay in between. The height is averaged over one orbit, and the gradual decrease is caused by atmospheric drag. As can be seen from the plot, the rate of descent is not constant and this variation is caused by changes in the density of the tenuous outer atmosphere due mainly to solar activity.

 

[MeteorWayne]

Knowing all that, would it be wise for NASA to buy or barter for an increased frequency of ATV visits from 1 a year to 2 a year or 2 every 9 months? The incredible reboots capability of this vehicle is worth it alone in light of shuttle's retirement!

Anyone know what the ISS's current altitude is and how we can see it on a graph over time?

Also, if Congress grants approval for STS-135, the cost would cover another year for shuttle personnel employment. If we extend their employment, it wouldn't be a stretch to add an additional flight for the other two orbiters. I believe there's leftover hardware to support another 2 or 3 flights. I say if we can justify another mission for each orbiter, let's do it! We could, for example, send Node 4 up, maybe the Centrifuge Accomidation Module if we can rehabilitate it, and convert at least another MMLP into another PLM.

One last question: Does anyone know what altitude they're planning on raising ISS after the shuttle's retire?

Last year of ISS altitude:


http://heavens-above.com/IssHeight.aspx ... t=0&tz=CET

Longer time period, but ending in 2009:

http://en.wikipedia.org/wiki/File:Inter ... mb_version).png

I may merge this with the existing ATV 2 thread:

viewtopic.php?f=6&t=24845

depending on where the conversation heads.

from that thread:

"Interesting bit in the above link about the planned reboost of the ISS just prior to the ATV2's departure from the ISS:

"The ATV's engines will burn about 4,000 kilograms, or 8,800 pounds, of propellant to raise the station's altitude next spring after the final scheduled space shuttle flight in February and March.
The orbit boost will amount to about 40 kilometers, or 25 miles. The station will need fewer reboosts in the future when flying in the higher orbit, which subjects the complex to less drag.
If NASA adds an extra shuttle flight, it will have to reach the station in a higher orbit, meaning it will not be able to carry quite as much cargo as previous missions.
The STS-135 flight is penciled into NASA's manifest for launch in late June, after the ATV is scheduled to depart.""

That will put it at ~ 390 km, about as high as it's ever been.


MW

 

[newtons_laws]

By the way here is a graph of the ISS altitude. I don’t think the ISS altitude is going to be raised too much as it depends on the Earth’s atmosphere to protect the astronauts on board.
http://en.wikipedia.org/wiki/File:Internationale_Raumstation_Bahnhöhe_(dumb_version).png

I think you're mistaken when you say "it depends on the Earth's atmosphere to protect the astronauts on board" - the ISS at its present altitude is already in a pretty darn good vacuum (apart from the few remaining molecules of the atmosphere which because of their slight drag do degrade the orbit over time). The astronauts on board are protected from ionising radiation by two mechanisms: firstly the ISS walls themselves which absorb some radiation and secondly the Earth's magnetic field which diverts incoming charged particles only (not X or Gamma rays). An increase of 40km altitude to the ISS would I think make little difference as the Earth's magnetic field extends well beyond this, but higher orbits such as geosynchronous ones may well be affected. See http://www.esa.int/TEC/Space_Environmen ... LZE_0.html

 

[stevekk]

I absolutely agree that more frequent missions are appropriate.
I also like the idea of a modification / enhancement to allow its use fir emergency escape from the ISS.

I believe the number of ATV launches is completely dependant on the number of astronauts the Europeans get to send us to the ISS. More ATV flights needs fewer Americans on the ISS.

I wonder if adding the extra 25 miles to the ISS orbit will affect how much cargo will be delivered on the other cargo craft. Does this lighten the load that a Dragon or Progress can carry ? I wonder if SpaceX had to make any software mods to account for the new ISS orbit.