SpaceX lost a Facebook Internet satellite in 2016, when the Falcon 9 which was supposed to carry it into space exploded during preflight preparations.
Mr McDowell said it was not plausible that the loss of Zuma is a fabrication to conceal its successful insertion in a secret orbit. Those who watched the launch observed that the Falcon 9 did successfully take off, which would indicate that the rocket itself worked, and SpaceX has tweeted several times about the rocket's launch and landing.
On Monday evening, it was reported that the payload fell to the Earth along with the second stage of the Falcon 9 rocket. She added that the company cannot comment further due to the classified nature of the mission. Also, the company continued with preparations for future launches, including rolling the Falcon Heavy rocket back out to a different launch pad in Florida for additional tests.
A highly classified payload known by the code name Zuma and believed to be a spy satellite was lost after its launch by SpaceX, reports said Tuesday.
The US government had assigned Northrop Grumman - the Virginia-based aerospace and defence company that built the spacecraft, the responsibility of acquiring launch services for this mission.
The news wire quoted two sources as saying the satellite is assumed to have broken up or plunged into the sea.
The launch was delayed from November so SpaceX, founded by Tesla's (TSLA) Elon Musk, could analyze data from the protective nose cone from another launch.
Blast-off for the Zuma mission on Sunday. It was so shrouded in secrecy that the sponsoring government agency was not even identified, as is usually the case.
"Since the data reviewed so far indicates that no design, operational or other changes are needed, we do not anticipate any impact on the upcoming launch schedule", Shotwell added.
Sunday night's launch will be streamed online.
SpaceX, run by entrepreneur Elon Musk, has sent more than a dozen resupply missions to the International Space Station, most recently in December.
Last week, SpaceX finally declared that both the rocket and the payload were "healthy" and ready for launch. Northrup Grumman isn't commenting on the outcome, citing the classified nature of the mission.
"We have nothing to add to the satellite catalog at this time", Navy Captain Brook DeWalt, a spokesman for the command, wrote in an email to Bloomberg.