CAPE CANAVERAL — SpaceX will reboot its launch effort for NASA’s TESS satellite on Wednesday, with a 30-second window opening at 6:51 p.m.
It was scrubbed hours before the Monday window when the space company decided to conduct more analysis of the guidance, navigation and control systems.
This mission’s navigation includes getting the satellite close to the Moon, so it can slingshot around and enter an elliptical orbit.
Forecast was almost perfect with 90% favorable weather outlook, only a slight concern that cumulus clouds might get really big.
“Winds will become southeasterly and a few low-topped cumulus clouds may form after noon over the Spaceport,” said the latest forecast from the Air Force’s 45th Weather Squadron. “The primary weather concern is a slight chance of cumulus reaching 15,000 feet. Maximum upper-level winds will be from the northwest at 50 knots near 37,000 feet.”
NASA said Monday that the “TESS spacecraft is in excellent health, and remains ready for launch.”
TESS will launch on a Falcon 9 rocket from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida.
TESS, which stands for Transiting Exoplanet Survey Satellite, is a telescope/camera that will hunt for undiscovered worlds around nearby stars, providing targets where future studies will assess their capacity to harbor life, NASA says.
With the help of a gravitational assist from the Moon, the spacecraft will settle into a 13.7-day orbit around Earth.
The spacecraft will be looking for a phenomenon known as a transit, where a planet passes in front of its star, causing a periodic and regular dip in the star’s brightness. NASA’s Kepler spacecraft used the same method.
TESS is designed to concentrate on stars less than 300 light-years away.
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Artist's representation of the Transiting Exopanet Survey Satellite. 
On Wednesday at 6:51 p.m. local time (2251 ), a SpaceX  launched from  Air Force Base in Florida, United States, carrying, as a payload for the US National Aeronautics and Space Administration (NASA), the  (TESS).  NASA designed TESS to search for exoplanets circling stars mostly within 300 light-years of the .

Officially a NASA Astrophysics Explorer mission, much of the TESS program is to be run from the Massachusetts Institute of Technology's (MIT) Kavli Institute for Astrophysics and Space Research in cooperation with the . "One of the biggest questions in exoplanet exploration is: If an astronomer finds a planet in a star's habitable zone, will it be interesting from a biologist's point of view?" TESS principal investigator George Ricker told the press, "We expect TESS will discover a number of planets whose atmospheric compositions, which hold potential clues to the presence of life, could be precisely measured by future observers."

A little more than an hour after launch, NASA and SpaceX teams announced the satellite was up and functioning and had deployed its solar panels. Most launches have a roughly two-hour period during which the mission can be executed, but this one had a window of only thirty seconds because this satellite must use the Moon's gravity to reach the desired orbit.

TESS is slated to enter a high orbit distinct from the geosynchronous orbits used by many other satellites.  TESS instrument scientist Joel Villasenor, also of MIT, explained, "The Moon and the satellite are in a sort of dance. The Moon pulls the satellite on one side, and by the time TESS completes one orbit, the Moon is on the other side tugging in the opposite direction. The overall effect is the Moon's pull is evened out, and it's a very stable configuration over many years. Nobody's done this before, and I suspect other programs will try to use this orbit later on."

If all goes according to plan, TESS will circle the Earth for 60 days to establish its 13.7-day orbit and test its machinery before beginning its mission: using its four cameras to analyze stars for decreases in brightness that may be caused by a planet passing between us and them, a technique called the .  TESS's launch comes just as the , launched into orbit around the Sun 2009, is about to run out of fuel.  Scientists used Kepler to identify at least over 2300, perhaps over 4500 planets and gather data on stars and black holes.  TESS is designed to cover 400 times as much of the sky as Kepler, and is capable of viewing 85% of the sky.  Scientists expect it to find 1500 planets during its two-year mission, 300 Earth-like, but believe it may find many more.

Because TESS's cameras can cover a wide range of radiant energy, including infrared, scientists believe it may be able to detect planets orbiting , which scientists consider likely to host rocky, Earth-like planets with the right mass for an atmosphere and the right temperature to host liquid water, a range called the .

The data collected by TESS are to be publicly accessible so anyone who wishes may participate in the search. NASA plans to process the data, about 27 gigabytes collected per day, using a supercomputer called .

The original schedule had launch at 6:32 p.m. on Monday evening but it was postponed so the SpaceX team could perform more guidance navigation control tests before launch.

SpaceX is a private company that has partnered with NASA before on such missions as resupplying the International Space Station.



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