Two back-to-back launches by SpaceX and Blue Origin will have to wait a bit longer for liftoff after technical issues forced both companies to call off launch attempts scheduled for today (Dec. 19).

It's the second day of launch delays for both companies. On Tuesday, a ground equipment issue forced Blue Origin to call off the attempted suborbital launch of its New Shepard spacecraft from West Texas. A short time later, a sensor issue on a SpaceX Falcon 9 rocket delayed the launch of a new GPS III navigation satellite for the U.S. Air Force from Florida's Cape Canaveral Air Force Station.

This morning, SpaceX representatives said the company is still studying the sensor issue that twarted Tuesday's launch attempt.

"Standing down from today's launch attempt of GPS III SV01 to further evaluate out of family reading on first stage sensors; will confirm a new launch date once complete," they said in a Twitter update.

Meanwhile, Blue Origin is now targeting a Friday launch for its resuable New Shepard rocket and space capsule. The rocket is carrying nine NASA-sponsored experiments into space, but won't go into orbit as New Shepard is built for suborbital flights only.

"Still working through ground infrastructure issues and monitoring incoming weather in West Texas," Blue Origin representatives wrote on Twitter. "Slating next launch window NET Friday 12/21 pending further review."

While the SpaceX and Blue Origin launches are on hold, two other missions that were also delayed on Tuesday will attempt to launch today.

A SpaceX Falcon 9 rocket carrying the GPS III SV01 navigation satellite for the U.S. military stands atop its launchpad ahead of a Dec. 18, 2018 launch attempt from Cape Canaveral Air Force Station in Florida. (Image credit: SpaceX)

An Arianespace Soyuz rocket is scheduled to launch the CSO-1 spy satellite for the French military at 11:37 a.m. EST (1637 GMT) from the Guiana Space Center in Kourou, French Guiana. Later, a United Launch Alliance Delta IV Heavy rocket will launch the U.S. NROL-71 spy satellite from California's Vandenberg Air Force Base at 8:44 p.m. EST (0144 Dec. 20 GMT). Both launches were delayed Tuesday by unacceptably high winds over their respective launch sites.

You can watch the ULA launch live on Space.com, courtesy of ULA, beginning at about 8:24 p.m. EST (0124 GMT).

Another space mission has already successfully launched today: The Indian Space Research Organisation successfully launched the GSAT-7A communications satellite at 5:40 a.m. EST (1040 GMT) from the Satish Dhawan Space Centre in Sriharikota, India. The mission launched on India's upgraded Geosynchronous Satellite Launch Vehicle and is the third launch for India in just over a month, according to the Times of India.

Finally, a Russian Soyuz spacecraft will return to Earth with three members of the International Space Station's crew tonight. The Soyuz is due to undock from the space station at 8:42 p.m. EST (0142 Dec. 20 GMT) and land in a remote region of Kazakhstan early tomorrow at 12:03 a.m. EST (0503 GMT). You can watch that Soyuz landing on Space.com today.

Email Tariq Malik at tmalik@space.com or follow him @tariqjmalik. Follow us @Spacedotcom and Facebook. Originally published on Space.com.