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posted by janrinok on Wednesday March 28 2018, @08:08PM   Printer-friendly
from the weighty-problem dept.

NASA chief explains why agency won't buy a bunch of Falcon Heavy rockets

Since the launch of the Falcon Heavy rocket in February, NASA has faced some uncomfortable questions about the affordability of its own Space Launch System rocket. By some estimates, NASA could afford 17 to 27 Falcon Heavy launches a year for what it is paying annually to develop the SLS rocket, which won't fly before 2020. Even President Trump has mused about the high costs of NASA's rocket. On Monday, during a committee meeting of NASA's Advisory Council, former Space Shuttle Program Manager Wayne Hale raised this issue. Following a presentation by Bill Gerstenmaier, chief of human spaceflight for NASA, Hale asked whether the space agency wouldn't be better off going with the cheaper commercial rocket.

[...] In response, Gerstenmaier pointed Hale and other members of the advisory committee—composed of external aerospace experts who provide non-binding advice to the space agency—to a chart he had shown earlier in the presentation. This chart showed the payload capacity of the Space Launch System in various configurations in terms of mass sent to the Moon. "It's a lot smaller than any of those," Gerstenmaier said, referring to the Falcon Heavy's payload capacity to TLI, or "trans-lunar injection," which effectively means the amount of mass that can be broken out of low-Earth orbit and sent into a lunar trajectory. In the chart, the SLS Block 1 rocket has a TLI capacity of 26 metric tons. (The chart also contains the more advanced Block 2 version of the SLS, with a capacity of 45 tons. However, this rocket is at least a decade away, and it will require billions of dollars more to design and develop.)

SpaceX's Falcon Heavy TLI capacity is unknown, but estimated to be somewhere between 18 and 22 tons (between the known payloads of 16.8 tons to Mars and 26.7 tons to geostationary orbit).

Does the SLS need to launch more than 18 tons to TLI? No. All of the currently planned components of the Lunar Orbital Platform-Gateway (formerly the Deep Space Gateway) have a mass of 10 tons or less due to flying alongside a crewed Orion capsule rather than by themselves. Only by 2027's Exploration Mission 6 would NASA launch more massive payloads, by which time SpaceX's BFR could take 150 tons to TLI or even Mars when using in-orbit refueling.

Related: NASA Eyeing Mini Space Station in Lunar Orbit as Stepping Stone to Mars
NASA and Roscosmos Sign Joint Statement on the Development of a Lunar Space Station
President Trump Signs Space Policy Directive 1
Russia Assembles Engineering Group for Lunar Activities and the Deep Space Gateway
After the Falcon Heavy Launch, Time to Defund the Space Launch System?
President Trump Praises Falcon Heavy, Diminishes NASA's SLS Effort

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  • (Score: 2) by turgid on Thursday March 29 2018, @08:50PM (2 children)

    by turgid (4318) Subscriber Badge on Thursday March 29 2018, @08:50PM (#660187) Journal

    That's a dishonest answer as usual. Rockets don't need large TLI capacity for Lunar expeditions. Assemble the rocket in LEO (Low Earth Orbit), and then when fully assembled, fueled, tested, and loaded, send it on its way.

    And do you want to go to the Moon in 5 years or 25 years? When was the last time anyone had the technology (developed, tested, reliable) to assemble large rockets in orbit?

    Everything's easy when you're a bean counter.

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  • (Score: 1) by khallow on Thursday March 29 2018, @09:25PM

    by khallow (3766) Subscriber Badge on Thursday March 29 2018, @09:25PM (#660207) Journal

    And do you want to go to the Moon in 5 years or 25 years?

    Falcon Heavy flies right now. SLS may never fly.

  • (Score: 1) by khallow on Thursday March 29 2018, @09:39PM

    by khallow (3766) Subscriber Badge on Thursday March 29 2018, @09:39PM (#660213) Journal
    I'll also note that we could have already had a lunar presence, if we had done such assembly with the variety of 20-25 metric ton rockets available to us around the world. It'd be more work, but it's something we could have started in 1970 rather than 2022.

    I think that bears repeating. We could have had several SpaceXs created in 1970 instead of 2002. All that crazy space stuff could be done by now rather than still being some indefinite 5 years, 25 years, or maybe longer in our future.

    My view is that there is no manned lunar program because it's not going to survive the funding drain from SLS. Kill SLS, stake through the heart, then we have money to work with.