Saturday, January 28, 2017

Space exploration!

A paragraph from the article listed that is critical to the exploration of space!

The Case to Save the Shuttle
By Allen J. RichardsonPosted 10.14.08NOVA

MANNED SPACE VEHICLE EXPLORATION UTILIZING THE SPACE SHUTTLE
The space shuttles, used in concert with the International Space Station (ISS), could provide a viable means of launching manned space vehicles to destinations in our solar system, such as the moon, Mars, or an asteroid. In a single launch, the space shuttle can orbit a 50,000 lb payload, a capability that has allowed us to construct and operate the ISS, which weighs one million lbs. By designing the interplanetary vehicles in modular form and assembling them in orbit utilizing the ISS, we can assemble vehicles of enormous size, if required. This capability would be of indispensable value in the case of a Trans Mars vehicle, which would require the transport of considerable energy to power the vehicle there and back. Should additional single payload launch capability (either in weight or size) be required, a Space Shuttle-C (an unmanned space shuttle variant with increased payload capability) could be built. An additional benefit of this approach is that the ISS could serve as a mission return stopping point, followed by space shuttle transport of astronauts to Earth. This could provide an extra margin of safety for astronauts with unforeseen needs.
The specific advantages of continuing the space shuttle approach to solar system exploration discussed above, as opposed to the current Constellation "space shuttle replacement" approach, are numerous:
1) The space shuttle is a proven and predictable system. In contrast, the Ares-1 Launch Vehicle (ALV) is already beset with technical uncertainties regarding weight limitations and excessive vibration.
2) The space shuttle system is a combination of launch vehicle and spacecraft. The space shuttle Orbiter's on-orbit capabilities include a remote arm capable of manipulating and repairing satellites. The Orbiter also includes an airlock to support extravehicular activities such as space repairs and component assembly. The Constellation system (the shuttle replacement) is a combination of the ALV and the Orion spacecraft. The Orion spacecraft does not have the above capability.
3) The space shuttle system can return both payloads and astronauts from orbit to Earth via a runway landing, while the Constellation approach will revert to parachuting a capsule and the returning astronauts into the ocean, as was the case with the Apollo system.
4) The space shuttle will provide uninterrupted U.S. support to the ISS. Pursuing the Constellation approach will result in a gap of five years or more, when the U.S. will have no capability of delivering supplies to the ISS or of delivering astronauts to the ISS and returning them. Relying on the Russians to fill this gap has become more problematic with the controversy over the Russian invasion of Georgia and the reluctance of the U.S. Congress to renew the legislative exemption that enables NASA to continue to purchase Soyuz spacecraft services as a backup to the space shuttle. The current exemption expires in 2011. Therefore, Congress will need to extend the exemption till the ALV/Orion system is operational.
5) The space shuttle approach will insure ongoing utilization of the ISS, a space colony that humankind should keep in place and operating for the foreseeable future.
6) With the space shuttle system, both the Orbiter and the SRBs are reusable. With Constellation, a relatively larger part of the system, the ALV, is a single-use component.
7) The space shuttle and supporting facilities are paid for!
The advantages of the Constellation approach over the space shuttle approach appear to be nil, the switch to the Constellation approach being predicated primarily on the unwarranted fear of another shuttle "accident" as put forward by the President's CAIB. Fortunately, there is time to reconsider. Even though the dismantling of the space shuttle system has begun, it probably would be more advantageous to stay with this system than to design and construct a whole new system to support the Constellation program. At a minimum, the shuttle system should be extended till its replacement is operational.
The next President and his NASA administrator should also consider a change in the next goal of the U.S. manned space program as well as a change in the hardware to achieve that goal. Scientific interest now centers on Mars rather than on the moon. Four of the five elements of a manned mission to Mars are already in place:
1) The space shuttle (the launch vehicle)
2) The International Space Station, or ISS (the assembly and launch platform for the Trans Mars vehicle)
3) Extensive experience with on-orbit assembly
4) Numerous unmanned precursor missions to Mars
The only missing element is the Mars Aerobraker Vehicle (MAV) to transport the expected three astronauts to and from Mars. Conceptual designs already exist for this vehicle. At an estimated departure weight of 400,000 pounds, a dozen shuttle flights could deliver all needed modules of the MAV to the ISS over a period of years at a cost of perhaps $10 billion. This would leave most of $200 billion (the amount currently contemplated for lunar exploration) to design, build, and assemble the MAV. This redirection would focus the attention and resources of NASA and the aerospace community on the MAV, and would sharpen skills valuable to the nation for further exploration of our solar system. With the manned space program thus redirected, the goal of landing humans on Mars within the next decade appears to be feasible.
My e-mail address is alrichardson2@aol.com
On behalf of the members of SAT, thank you for your interest.
Allen J. Richardson,
Former Orbiter Stress Analysis Supervisor
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