For years, Musk proclaimed that SpaceX could save taxpayers millions by offering the Pentagon launches for far less than its chief rival. ULA, meanwhile, maintained that responsibility for national security satellites that cost hundreds of millions and help guide precision bombs and conduct surveillance should not just go to the lowest bidder.
Now with a launch for the National Reconnaissance Office scheduled for Wednesday, ULA is again poised to showcase its record of reliability with more than 100 consecutive launches without a failure. The launch comes as reports indicate that a highly classified satellite launched by SpaceX on Sunday may have suffered a failure once it reached space.
Known only by a codename, Zuma, the satellite was launched Sunday evening by SpaceX on its Falcon 9 rocket from Cape Canaveral Air Force Station. The mission is so secretive that it is not known which government agency commissioned the launch, what the satellite cost or what it would do once in orbit. The launch appeared to go smoothly, and SpaceX cheered a successful liftoff and then the touch down of its first-stage booster back on land. Musk on Monday tweeted out a long-exposure picture of the launch showing its fiery tail to space - and then the return of the booster.
The Air Force's 45th Space Wing also congratulated the company in a tweet: "What an incredible way to start off 2018 w/the world's 1st successful launch and land of this year!"
As word spread on Monday that something may have happened to the Zuma satellite, SpaceX maintained that nothing went wrong with its Falcon 9 rocket, saying a review of the data showed it "performed nominally."
Northrop Grumman, which manufactured the Zuma satellite, said in a statement that it could not comment on the mission because it was classified.
If something did go wrong with the mission, it's not clear what happened or who is to blame.
But even if SpaceX's Falcon 9 performed perfectly, it is not a good time for the company, founded by Musk in 2002, to have something happen to such an important payload.
For years, the company has been in a heated battle with ULA over lucrative contracts to launch national security payloads, long seen by Musk as a key source of revenue. SpaceX is also under contract from NASA to fly astronauts to the International Space Station, and it maintains that the first test flights with humans on board could happen as soon as this year.
For nearly a decade, ULA had a monopoly on Pentagon launches. In 2014, SpaceX sued the Air Force arguing that it should be able to compete for the contracts. In 2015, the parties settled, and SpaceX was granted the certification that allowed it to bid. Since then, SpaceX has won two of three competitively bid launches.
As they battled with SpaceX, ULA's executives launched a "results over rhetoric" campaign, highlighting the company's long heritage in space.
At the time, ULA's then-CEO accused SpaceX of trying to "cut corners" and "taking a dangerous approach." Under mounting pressure from SpaceX, he was fired, and ULA's new CEO, Tory Bruno, vowed to "literally transform" the company in order to compete with Musk - and he also continued to champion ULA's track record of successful launches.
SpaceX, meanwhile, had two high-profile incidents. In 2015, a rocket blew up while carrying cargo to the space station. Then in 2016, another rocket exploded while being fueled ahead of an engine test. No one was hurt in either explosion.
In both cases, the company was grounded while it investigated the cause of those problems. As of now, it appears SpaceX is going to keep moving ahead with its launch manifest, a sign that it is confident in its rocket's performance.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)