Payload for 2022 SLS Launch Still Up in the Air

Space Launch System and Orion spacecraft on Pad 39B. (Credit: NASA)

by Douglas Messier
Managing Editor

NASA has set mid-2022 for the second flight of the Space Launch System (SLS), but it’s not yet known what the massive booster will actually launch.

“Determination as to whether this launch will be SLS/Orion crewed mission (EM-2) or the SLS/Europa Clipper mission will be made based on risk and readiness of the Europa Clipper project,” according to a decision memo signed on Friday by William C. Hill, deputy associate administrator for Exploration Systems Development. Parabolic Arc obtained a copy of the memo.

EM-2 will be the first crewed flight of the Orion spacecraft. The mission will send up to four astronauts to the vicinity of the moon on a flight that will take them further out into space than the Apollo crews traveled.

This artist’s rendering shows a concept for a future NASA mission to Europa in which a spacecraft would make multiple close flybys of the icy Jovian moon, thought to contain a global subsurface ocean. (Credit: NASA/JPL-Caltech)

The Europa Clipper orbiter will make the first detailed survey of Jupiter’s frozen moon, which scientists believe hides an ocean beneath its icy surface. The mission will be followed by an Europa lander, whose launch is currently scheduled for 2024.

Both EM-2 and the Europa Clipper missions will use the SLS Block 1 configuration, which is capable of lifting 70 tons into low Earth orbit (LEO). The flights will use Mobile Launcher 1 (ML-1) “with minor modifications to support crewed flight (update to caution and warning system, implementation of emergency egress system),” the memo stated.

“Maintenance of ML-1 in the SLS Block 1 configuration allows for the launch of the Europa Clipper science mission on Block 1 as early as the June 2022 planetary window,” the memo added. “Current analysis show sufficient Block 1 capability to support a direct trajectory of Europa Clipper to the Jovian system, without need of Earth or Venus flybys, through the available launch windows in the 2020s.”

The document cancels an earlier decision memo that directed the implementation of the larger SLS Block 1B capability for the EM-2 mission. “Mission objectives of EM-2 can be achieved using SLS Block 1 with the ML-1 in the current SLS Block-1 configuration,” the memo said.

An artist rendering shows NASA’s Space Launch Systems (SLS) evolution from a Block 1 configuration to various configurations capability of supporting different types of crew and cargo missions. (Credit: NASA/MSFC)

The SLS Block 1B launcher will be capable of lifting 105 tons into LEO — a 50 percent increase over SLS Block 1. With the Orion crew vehicle, Block 1B will stand 364 feet (110.9 meters) tall – 42 feet (12.8 meters) taller than SLS Block 1.

NASA is constructing a second mobile launcher (ML-2) specifically designed to support the SLS Block 1B launcher and larger variants of the booster. “Planning should assume an SLS Block 1B launch using ML-2 in the first quarter of the calendar year 2024,” the memo stated.

ML-1 will be converted to support SLS Block 1B and later booster variants if funds become available.

  • Mr Snarky Answer
  • Terry Stetler

    At the rate EM-1 is moving right it and EM-2 may need to flip a quarter for 2022 pad rights.

  • passinglurker

    “The SLS Block 1B launcher will be capable of lifting 105 tons into LEO — a 50 percent increase over SLS Block 1.”

    This isn’t accurate after falcon heavy launched nasa finally admitted that block 1 is 95 tons to LEO(11% difference yay…). If sls was a more reasonable 70 tons to LEO we probably would be flying it already.

  • Zed_WEASEL

    Wasn’t the structure limits of the ICPS (aka DCSS) airframe limiting the Block 1 payload?

  • Antonio Fanella

    Why not use Falcon Heavy to launch the Europa Clipper orbiter in 2022?

  • passinglurker

    Apparently not cause 95tons is now the figure they use and nothing about block1 has changed

  • perilun

    Nice picture that looks like progress … my guess is the only time the SLS will fly will be in computer graphic simulations. Why not talk about block 3 and 4 to move the goal posts even further?

  • mattmcc80

    It’s too heavy for FH to do a direct flight, the mission would have to add a gravity assist maneuver.

  • Kirk

    “ML-1 will be converted to support SLS Block 1B and later booster variants if funds become available.”

    Doug, was that specifically mentioned in the memo? I don’t know why they would do that since a single Mobile Launcher should support their projected launch cadence, and didn’t earlier studies claimed that it would cost more to convert ML-1 to handle the Block 1B than to construct ML-2 from scratch?

  • Zed_WEASEL

    You need the SLS Block 1B for direct flight to Europa. Think the Block 1 and the the Falcon Heavy fully expended have roughly the same performance. So both will likely required a gravity assist.

    However the Europa Clipper have been decreed by Congressional fiat to be flown with a SLS of some sort at about $1.5B per flight plus the fixed infrastructure cost.

  • windbourne

    just do 2 FH flights, with 1 being a tug that will push the clipper. Simple to do and a fraction of the price.

  • Zed_WEASEL

    The 95 tonnes to LEO is for a 100 mile (160 km) circularized orbit. presuming that is statue miles.

  • Richard Malcolm

    That’s true – at least for the configuration of Europa Clipper being considered.

    Obviously, if the mass was reduced enough, Falcon Heavy could do the job. Apparently, they’re unwilling to do that.

  • passinglurker

    Most rockets put their leo reference orbit fairly low it won’t make a big enough difference to account for 35tons of sudden surplus capability.

  • Michael Halpern

    they would do it because the funds are available, obviously, because we need to support extremely large ground vehicle industry