NASA has announced that SpaceX’s Falcon 9 rocket – using a flight-proven booster – will launch the ~300 kg (670 lb) Imaging X-ray Polarimetry Explorer (IXPE) spacecraft no earlier than April 2021.



Intriguingly, IXPE was originally planned to launch on Orbital ATK (now Northrop Grumman’s) Pegasus XL but NASA never followed through with a launch contract. The move to SpaceX’s Falcon 9 rocket is likely related to the extremely disruptive and expensive launch delays NASA’s Ionospheric Connection Explorer (ICON) spacecraft has suffered at the hands of its Pegasus XL rocket. Capable of launching less than 450 kg (1000 lb) to low Earth orbit, Pegasus XL has been lucky to launch annually over the last decade or so and carries a price tag of no less than $50M-$60M today.

To add to this: NASA says SpaceX can use a previously flown booster on this mission.



IXPE is a small satellite, but this launch contract is less than what NASA paid for for the still-pending Pegasus XL launch of ICON ($56.3M in a 2014 contract). Think about that… https://t.co/sJlWVMHC5c — Jeff Foust (@jeff_foust) July 8, 2019

Small rocket, huge delays

Defying its small size, Pegasus XL was originally scheduled to launch ICON in December 2017. Delayed by unspecified problems with launch vehicle hardware, the mission was pushed back an inexplicable 10 months to October 2018, where additional issues with the rocket again indefinitely scrubbed a launch attempt. In early 2019, the launch was tentatively scheduled for Q2 2019, while – as of July – ICON is not expected to launch before September 2019.



All said and done, in the increasingly unlikely event that Pegasus XL is ready for launch this September, the ICON spacecraft – ready for launch since late-2017 – will have been delayed more than 21 months by problems with the rocket.

Built by Orbital ATK, Pegasus XL is a small rocket that carries a disproportionate price tag and a recent history of bad reliability. (NASA – Randy Beaudoin)

Again, for the small-scale performance of Pegasus XL, the rocket still carries a price tag of more than $50M – NASA’s ICON launch contract was valued at more than $56M. Conscious of this, SpaceX has managed to sway NASA to launch the small IXPE spacecraft on a flight-proven Falcon 9 at a cost of just $50.3 million, easily the lowest Falcon 9 launch contract cost ever publicized.



In recent months, SpaceX executives have made comments indicating that Falcon 9’s default base price – likely assuming a flight-proven booster – is now as low as $50M. July 8th’s NASA launch contract is the first direct confirmation of that exceptionally affordable pricing, likely also indicating that the base price for Falcon 9 is even lower for commercial customers with less stringent requirements.

New Falcon 9 booster B1045 rolls out to LC-40 ahead of SpaceX’s first dedicated NASA payload, the TESS exoplanet observatory. (SpaceX)

Barring an unexpected contract between now and IXPE’s expected April 2021 launch, the mission will probably be the first time that a dedicated flight-proven SpaceX rocket launches a scientific spacecraft for NASA. SpaceX’s next dedicated NASA launch – the ESA-built Sentinel 6A spacecraft – is scheduled to no earlier than November 2020 and is likely to fly on a new Falcon 9 booster.



In April 2019, NASA awarded SpaceX $69M for Falcon 9 to launch the agency’s Double Asteroid Redirect Test (DART) – an asteroid-impactor spacecraft – no earlier than June 2021. IXME is SpaceX’s second NASA launch contract win of 2019.

NASA’s IXPE spacecraft will be built by Ball Aerospace. (NASA)

According to NASA, “IXPE will fly three space telescopes with sensitive detectors capable of measuring the polarization of cosmic X-rays, allowing scientists to answer fundamental questions about these turbulent environments where gravitational, electric and magnetic fields are at their limits.”

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