Author Topic: Orion LEO Test Flight  (Read 8870 times)

Offline Steven Pietrobon

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Orion LEO Test Flight
« on: 05/13/2014 05:56 am »
According to the Human Exploration and Operations Committee of the NASA Advisory Council 14-15 April 2014 Exploration Strategy presentation

http://www.nasa.gov/sites/default/files/files/20140414_HEOC_ExplorationStrategy_TAGGED.pdf

Orion will spend 26 to 27 days in space for the Asteroid Rendezvous Mission (ARM) going to a Distant Retrograde Orbit (DRO), staying in the DRO and then returning.

My understanding is that the Orion Life Support System (LSS) won't be ready until EM-2 in 2021, which I presume will fly a demonstration of the ARM profile (EM-1 will also be flying that profile). The ARM would be in 2025.

As has been demonstrated on the ISS, although LSS may work on the ground, they may have problems when exposed to the microgravity environment and the loads provided by actual astronauts.

Thus, it seems to me that it would be unwise for the first flight of Orion with crew and an untested Life Support System (LSS) for a nearly three week mission in deep space.

With Apollo, the first crewed flight of the Apollo Command and Service Module (CSM) was Apollo 7, launched on a Saturn IB for a LEO mission of nearly 11 days, replicating the duration of a Lunar flight. This flight served in part to test the duration of the CSM, including its ability to provide adequate life support.

Thus, what is needed before EM-2 is a crewed test of Orion in LEO for a three week mission. However, other than an expensive Space Launch System flight, there is currently no vehicle rated to carry a crewed Orion into space. However, a Delta IV Heavy will be launching an uncrewed Orion for a test flight at the end of this year.

Thus, I propose the following mission profile to perform a crewed LEO test of Orion that has minimum mission costs. I assume that only one international docking adaptor (IDA) is available on the International Space Station.

1) Delta IV Heavy launches an uncrewed Orion into an ISS transfer orbit.
2) If a commercial crew vehicle (CCV) is already docked to ISS, this would depart with two US crew and two Russian crew before Orion docks. In case the CCV fails to redock after Orion departs, this crew can safely return to Earth. The two US crew can return on Soyuz if Orion also fails to dock with ISS.
3) Orion rendezvous with ISS
4) Dock or berth with the ISS forward port IDA. Options include
   a) Automatic rendezvous and docking
   b) Have the ISS robotic arm capture Orion and then berth it the IDA. This is probably the cheaper option.
5) Two US crewmembers enter Orion and undock from ISS
6) A practice rendezvous, docking and undocking is performed with ISS
7) If the CCV has previously undocked, it redocks with the station.
8) Orion performs a three week stay in LEO. If a problem develops that prevents return to Earth, the crew have the option of redocking with ISS.
9) Orion returns to Earth with the two US crew. The empty seats on the CCV can be filled with ballast cargo on its return to Earth.
« Last Edit: 05/13/2014 06:02 am by Steven Pietrobon »
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline Planetaryduality

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Re: Orion LEO Test Flight
« Reply #1 on: 05/13/2014 06:43 am »
Excellent post. I was unaware there were any specific candidate asteroids for the ARM. Looking forward to what become of this!
-Kyle

Offline A_M_Swallow

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Re: Orion LEO Test Flight
« Reply #2 on: 05/13/2014 07:16 am »
{snip}
Thus, what is needed before EM-2 is a crewed test of Orion in LEO for a three week mission. However, other than an expensive Space Launch System flight, there is currently no vehicle rated to carry a crewed Orion into space. However, a Delta IV Heavy will be launching an uncrewed Orion for a test flight at the end of this year.
{snip}

An alternative mission is:
1) Delta IV Heavy launches an uncrewed Orion into a LEO orbit.
2) A manned CST-100, Dragon or DreamChaser containing 4 astronauts is launched into the same orbit.  It will have been performing space flights for several years by this time.
3) The two spacecraft dock.  This is possible because the new NASA Docking System is androgynous.
4) The people transfer to the Orion and use the other spacecraft as a lifeboat.
5) After 3 weeks a pilot returns to the other spacecraft.
6) The hatches are closed.
7) The Orion returns to Earth.
8) The other spacecraft returns to Earth.

Offline Steven Pietrobon

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Re: Orion LEO Test Flight
« Reply #3 on: 05/13/2014 07:50 am »
Yes, that's certainly an option, although it would be more expensive as you need a dedicated CCV. Another possibility is that Orion still rendezvous at ISS, the CCV there has four US crew undock and then dock with Orion. Two US crew transfer over and then they undock (with Orion then performing a practice docking and undocking). The CCV then docks with the ISS with Orion performing a three week mission.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline pathfinder_01

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Re: Orion LEO Test Flight
« Reply #4 on: 05/13/2014 06:14 pm »
The ISS has two docking ports that could be used to host a commercial crew craft or Orion. There might be clearance issues on one of them but that is that. Orion in theory was to be able to stay 6 months in space either docked to a station or free flying.

All you would need to do in theory is launch Orion first, have it dock. It could carry extra supplies for the mission. Launch a CCREW craft second, 2 out of 3 of them have the ability to hold more than 4 crew. Dock at the ISS (it can support in surge mode up to 14 people). Transfer over and perform a test flight.  No need to leave the ISS under crewed or without it's lifeboat lifeboat.
« Last Edit: 05/13/2014 06:17 pm by pathfinder_01 »

Offline Steven Pietrobon

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Re: Orion LEO Test Flight
« Reply #5 on: 05/14/2014 06:19 am »
Thanks pathfinder_01. Yes, if two IDA ports are available, that would make sense. Do you know where the location of the second IDA would be?
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Online AnalogMan

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Re: Orion LEO Test Flight
« Reply #6 on: 05/14/2014 01:21 pm »
Thanks pathfinder_01. Yes, if two IDA ports are available, that would make sense. Do you know where the location of the second IDA would be?

Current nominal plan:

IDA #1 install on PMA2 (Node 2 Fwd) ~April 2015
PMA3 move from Node 3 Port to Node 2 Zenith ~June 2015
IDA #2 install on PMA3 ~Dec 2015

Offline Steven Pietrobon

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Re: Orion LEO Test Flight
« Reply #7 on: 05/15/2014 05:47 am »
Thanks AnalogMan. Presumably, the CCV would be docked at IDA2 with Orion at IDA1.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline TomH

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Re: Orion LEO Test Flight
« Reply #8 on: 05/17/2014 02:06 am »
Very smart, Steven. Sending the first manned crew off into deep space is an unnecessarily high risk. My only concern is that the LSS is not being subjected to real conditions during launch. My own preference is to put Orion on FH (F9 is going to be man rated anyway) only, make SLS into cargo only and never man rate it. Orion and FH are going to be ready long before SLS anyway so we should test them first, then go to deep space when SLS is ready (perhaps a bit sooner with no need to man rate).

Offline clongton

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Re: Orion LEO Test Flight
« Reply #9 on: 05/17/2014 10:30 am »
My own preference is to put Orion on FH (F9 is going to be man rated anyway) only, make SLS into cargo only and never man rate it.

SLS will be man rated by design. Everything about the vehicle, just like Falcon, is "designed" as man rated from the very beginning. It would take more time, effort and money to NOT man rate the SLS than to let its man rated design continue because so much would need to be started over to make it less capable than it was designed for.
« Last Edit: 05/17/2014 10:31 am by clongton »
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Offline newpylong

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Re: Orion LEO Test Flight
« Reply #10 on: 05/17/2014 01:29 pm »
Definitely. The only thing you could cut out and save a buck is the emergency egress facilities. But that's a drop in the bucket.

Offline M129K

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Re: Orion LEO Test Flight
« Reply #11 on: 08/29/2014 02:48 pm »
Very smart, Steven. [snip]
Two points:
1. SLS is not the pacing element, Orion is.
2. Not manrating SLS might've been a smart move back in 2011 but with most of the vehicle having passed CDR now, changing the design will only further hurt the schedule and increase the cost, for little benefit.

Offline Lars_J

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Re: Orion LEO Test Flight
« Reply #12 on: 08/29/2014 04:02 pm »
Very smart, Steven. [snip]
Two points:
1. SLS is not the pacing element, Orion is.
2. Not manrating SLS might've been a smart move back in 2011 but with most of the vehicle having passed CDR now, changing the design will only further hurt the schedule and increase the cost, for little benefit.

Orion is the only current payload for SLS, so of course SLS has to be man-rated.

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