TeamVision (Part 1)
I'm currently reading through the TeamVision proposal for streamlining the Vision for Space Exploration. It's a fascinating read that encompasses the work done by LockMart's human-rated Atlas team and the Direct Launcher team, but goes much further. It starts with the fundamental observation that an EELV-based VSE overlaps with the capabilities of the shuttle, while a shuttle-derived VSE overlaps with the capabilities of the EELV's. By splitting VSE into five development spirals (referred to as "eras" by the report's author,) the Framework CT software package can be used to create an optimal combination of shuttle-derived and EELV-derived elements to fulfill the Vision for Space Exploration.
The first era, "Manned Exploration Transition," covers the period from today through the end of the ISS program. The objective is to resupply and inhabit the space station until its retirement. To that end, TeamVision recommends use of Delta and Atlas rockets and an optimized Block I Orion spacecraft.
Unlike LockMart, TeamVision isn't afraid to fly their man-rated Atlas with SRB's. The rationale is that, while we value human crews more than we value even the most expensive satellites, we still take every precaution to ensure mission success for our EELV launches. Based on the statistical records of the Delta and Atlas families (plus a 95% reliable escape rocket on the capsule,) it's assumed that loss-of-crew accidents will take place on less than 2% of all launches. TeamVision dismisses the need for desigining launchers to "man-rated" specifications, as the "man-rated" shuttle's failure rate is little better than the expected loss-of-crew rate for the Atlas V (with Delta IV only being used for cargo missions.)
While NASA's current Orion design weighs in at 25 metric tons, the Block I Command & Service Module in the TeamVision proposal is just over 17 mT, including escape system. The reason is that the Service Module is sized for orbital insertion and de-orbit from ISS rather than lunar missions. The rationale here is that it's premature for NASA to determine the SM requirements this early in the design process, before its lunar objectives have been totally fleshed out. Again, I would agree. The Apollo SM was actually oversized, based on a need to lift off directly from the lunar surface (back when NASA was debating Direct Descent/Ascent vs. Earth Orbit Rendezvous.) This time, we'll need to stretch the Block I SM to the Block II configuration, but only after we get into the second development "era." TeamVision does agree with NASA and LockMart on their re-use of the shuttle's OMS engines for the Orion SM engine.
So far, I'm really liking what TeamVision has to say. Their ideas are very logical. My biggest disappointment thus far has been some missing details on the cost of infrastructure for their proposed launchers and spacecraft. For example, a manned Atlas V will require crew access to the capsule atop the rocket; then again, this was already addressed in LockMart's studies (such as a crew elevator added to the existing Atlas launch tower.)
Competition between all-EELV-derived and all-Shuttle-derived approaches might result in a better system, but we live in a world where the government will only fund one approach. The hope of TeamVision, a hope that I share, is that we'll end up funding the optimal combination of shuttle-derived and EELV-derived elements to make the Vision succeed.
The first era, "Manned Exploration Transition," covers the period from today through the end of the ISS program. The objective is to resupply and inhabit the space station until its retirement. To that end, TeamVision recommends use of Delta and Atlas rockets and an optimized Block I Orion spacecraft.
Unlike LockMart, TeamVision isn't afraid to fly their man-rated Atlas with SRB's. The rationale is that, while we value human crews more than we value even the most expensive satellites, we still take every precaution to ensure mission success for our EELV launches. Based on the statistical records of the Delta and Atlas families (plus a 95% reliable escape rocket on the capsule,) it's assumed that loss-of-crew accidents will take place on less than 2% of all launches. TeamVision dismisses the need for desigining launchers to "man-rated" specifications, as the "man-rated" shuttle's failure rate is little better than the expected loss-of-crew rate for the Atlas V (with Delta IV only being used for cargo missions.)
While NASA's current Orion design weighs in at 25 metric tons, the Block I Command & Service Module in the TeamVision proposal is just over 17 mT, including escape system. The reason is that the Service Module is sized for orbital insertion and de-orbit from ISS rather than lunar missions. The rationale here is that it's premature for NASA to determine the SM requirements this early in the design process, before its lunar objectives have been totally fleshed out. Again, I would agree. The Apollo SM was actually oversized, based on a need to lift off directly from the lunar surface (back when NASA was debating Direct Descent/Ascent vs. Earth Orbit Rendezvous.) This time, we'll need to stretch the Block I SM to the Block II configuration, but only after we get into the second development "era." TeamVision does agree with NASA and LockMart on their re-use of the shuttle's OMS engines for the Orion SM engine.
So far, I'm really liking what TeamVision has to say. Their ideas are very logical. My biggest disappointment thus far has been some missing details on the cost of infrastructure for their proposed launchers and spacecraft. For example, a manned Atlas V will require crew access to the capsule atop the rocket; then again, this was already addressed in LockMart's studies (such as a crew elevator added to the existing Atlas launch tower.)
Competition between all-EELV-derived and all-Shuttle-derived approaches might result in a better system, but we live in a world where the government will only fund one approach. The hope of TeamVision, a hope that I share, is that we'll end up funding the optimal combination of shuttle-derived and EELV-derived elements to make the Vision succeed.
Labels: Launch vehicles, manned spacecraft, NASA, TeamVision, Vision For Space Exploration
posted by Mr. X at
7:57 PM
