A Japanese rocket designed to make launches cheaper and more efficient blasted off from southern Japan on Saturday, achieving success on its first flight with a compact telescope to peer at Mars, Venus and Jupiter and study their response to blasts of solar wind. Read our full story.

SPACECRAFT SEPARATION. The SPRINT-A satellite, fitted with a compact telescope, has been deployed from the Epsilon rocket to start a one-year mission observing how the solar wind impacts atmospheres and magnetospheres of planets, such as Venus, Mars and Jupiter.

SPACECRAFT SEPARATION. The SPRINT-A satellite, fitted with a compact telescope, has been deployed from the Epsilon rocket to start a one-year mission observing how the solar wind impacts atmospheres and magnetospheres of planets, such as Venus, Mars and Jupiter.

T+plus 60 minutes, 15 seconds. Cutoff of the Post Boost Stage is confirmed. The rocket is now maneuvering to release the SPRINT-A satellite in about one minute.

T+plus 58 minutes. As the final burn of the Post Boost Stage continues, the rocket is flying 1,153 kilometers over Chile.

T+plus 57 minutes. JAXA confirms the Post Boost Stage is firing again. This burn should continue until T+plus 60 minutes, 30 seconds.

T+plus 50 minutes. Ignition of the Epsilon's Post Boost Stage is coming up in a few minutes. The rocket is flying over the Pacific Ocean approaching the coast of Chile.

T+plus 27 minutes. The liquid-fueled upper stage has completed the first of two burns before deployment of the SPRINT-A payload.

The second burn, due to last nearly 7 minutes, will begin at T+plus 53 minutes, 50 seconds.

T+plus 25 minutes. The Post Boost Stage continues its burn. JAXA says the rocket is flying smoothly.

T+plus 19 minutes, 30 seconds. The eight thrusters on the Post Boost Stage are now firing. This liquid-fueled system is designed to accurately inject payloads into precise orbits, and two PBS burns are required for this mission. This first firing is set to last nearly 11 minutes.

T+plus 17 minutes. The third stage has separated on time. The first ignition of the Epsilon's hydrazine-fueled Post Boost Stage, or PBS, is set for T+plus 19 minutes, 8 seconds.

T+plus 12 minutes, 20 seconds. The third stage KM-V2b motor has consumed all its propellant, and the rocket is in another ballistic coast for the next 7 minutes. Separation of the third stage and the Epsilon's liquid-fueled orbit adjust stage is expected at T+plus 16 minutes, 48 seconds.

T+plus 10 minutes, 40 seconds. The Epsilon's second stage has jettisoned and the third stage has begun its 89-second burn.

T+plus 9 minutes. At T+plus 10 minutes, 24 seconds, the Epsilon's second and third stages will separate, followed moments later by ignition of the third stage.

T+plus 8 minutes. The rocket is now traveling on a ground track south of Tokyo at nearly 4 kilometers per second at an altitude of about 700 kilometers.

T+plus 4 minutes, 40 seconds. The second stage M-34c motor has burned out as planned, putting the Epsilon rocket in another coast phase lasting nearly 6 minutes.

T+plus 3 minutes, 45 seconds. The second stage continues firing normally.

T+plus 2 minutes, 50 seconds. The Epsilon's second stage is now firing after releasing the spent first stage.

T+plus 2 minutes, 40 seconds. JAXA confirms the 8.2-foot diameter payload fairing has been jettisoned now that the rocket is out of the dense lower atmosphere.

T+plus 2 minutes. The rocket's solid-fueled first stage motor has burned out, and the rocket is now in its first coast phase.

T+plus 60 seconds. The Epsilon rocket is soaring east from the Uchinoura Space Center, climbing into mostly cloudy skies as it surpasses the speed of sound.

LIFTOFF of Japan's first Epsilon rocket, a high-tech pathfinder for the future of affordable space launches.

T-minus 60 seconds. The countdown is running on an automatic computer-controlled sequencer.

At T-minus 55 seconds, the Epsilon rocket will be switched to internal power. The launcher's pyrotechnic systems will be armed at T-minus 26 seconds. The launcher's computer will be switched to flight preparation mode at T-minus 22 seconds.

T-minus 2 minutes. JAXA reports the Epsilon rocket is ready to launch.

Coming up in the next two minutes, computers will prepare the Epsilon rocket for liftoff. The automatic countdown sequence is due to begin at T-minus 70 seconds.

T-minus 2 minutes, 30 seconds. Weather conditions at the Uchinoura Space Center are cloudy with a temperature of 82 degrees Fahrenheit. Winds are out of the east-northeast at about 8 mph.

T-minus 3 minutes. The range system and safety system are reported ready.

T-minus 5 minutes. There are no problems reported at this point in the countdown.

After liftoff, the rocket will be tracked by communications stations at the Uchinoura launch site, JAXA's Tanegashima Space Center southwest of the launch site, JAXA's tracking site on the Ogasawara Islands south of Tokyo, JAXA's ground station on Christmas Island in the Pacific Ocean, and a Swedish-owned antenna in Santiago, Chile.

T-minus 10 minutes. Today's mission is the first space launch from the Uchinoura Space Center since September 2006, when the final M-5 rocket took off with the Hinode solar observatory. Uchinoura is located in the Kagoshima prefecture on the southern shore of Kyushu, the southernmost of Japan's main islands.

T-minus 15 minutes. The final satellite launch sequence begins now. In a few moments, the 767-pound SPRINT-A payload will be switched to internal power and removed from ground electrical supplies. The battery will power the satellite until it extends its solar arrays, which extend 23 feet tip-to-tip.

T-minus 18 minutes. The latest report from the launch team indicates all parameters are "go" for an on-time launch at 0445 GMT (12:45 a.m. EDT; 1:45 p.m. Japan time).

The Epsilon rocket stands 80 feet tall, is 8.2 feet in diameter, and weighs about 200,000 pounds at the time of liftoff.

T-minus 20 minutes. Please refresh this page to ensure you are viewing the launch webcast.

Liftoff has been reset for 0500 GMT (1 a.m. EDT), according to JAXA. The launch window extends until 0530 GMT (1:30 a.m. EDT).

T-minus 30 minutes. You can follow the launch with this timeline of major events and a map showing the rocket's ground track over the Pacific Ocean.

T-minus 60 minutes.

T-minus 2 hours. After liftoff, the Epsilon rocket will east from the Uchinoura Space Center and deliver the SPRINT-A planetary astronomy satellite about an hour after launch. The four-stage rocket will propel the 767-pound payload into an orbit with a low point of 590 miles, a high point of 714 miles, and an inclination of 31 degrees.

The Epsilon rocket's first stage, derived from solid rocket boosters used on Japan's larger H-2A and H-2B rockets, will fire for nearly 2 minutes and generate 510,000 pounds of thrust to power the Epsilon rocket to an altitude of 54 miles.

The launcher's first and second stages, named the M-34c and KM-V2b, are based on motors used on Japan's M-5 rocket, the Epsilon's predecessor. A liquid-fueled Post Bost Stage, or PBS, will ignite two times to accurately inject SPRINT-A into the correct orbit.

Launch preparations are proceeding as planned for the first launch of Japan's Epsilon rocket at 0445 GMT (12:45 a.m. EDT; 1:45 p.m. Japan time).

The 80-foot Epsilon rocket is being removed from its protecting gantry-like enclosure now. The launcher will be rotated atop a pedestal over the launch pad's flame trench, then the rocket will be powered up for prelaunch testing.

The launch pad at Uchinoura, which was previously used by Japan's M-5 rocket program, is unique in that the rocket is housed inside a gantry during assembly, then the launcher and its umbilical tower rotate out of the protective structure and lock into position over the flame trench. Most launch pads feature either mobile assembly towers or "clean pad" designs, in which the launch vehicle moves to the launch site from an integration building hundreds of meters away.

The Epsilon launcher is designed to reduce the time and costs required to prepare rockets for flight. Engineers designed the rocket to autonomously check its own health and devised a ground control architecture in which the launch team could oversee the Epsilon's countdown from laptop computers.

Final launch preparations are on schedule for the launch of Japan's solid-fueled Epsilon rocket at 0445 GMT (12:45 a.m. EDT) Saturday on its first demonstration flight.

The 80-foot-tall rocket, outfitted with smarts and designed for autonomy, has 45 minutes to blast off Saturday from the Uchinoura Space Center in southern Japan.

It will be the second launch attempt for the Epsilon rocket, which was grounded Aug. 27 in the final minute of the countdown by a disparity in telemetry indicating the rocket was tilting.

Engineers say the launcher really wasn't leaning, and an investigation found a slight time lag in the communications between the rocket's computer and the launch control center.

Officials resolved the issue and the problem did not appear when controllers put the rocket through a countdown rehearsal Sept. 8.

The next launch attempt for Japan's new Epsilon rocket is scheduled for no earlier than Sept. 14 after a last-minute hold in the launcher's first countdown in late August, according to the Japan Aerospace Exploration Agency.

The countdown was halted at T-minus 19 seconds on Aug. 27, when the rocket's on-board computer detected a change in the attitude of the 80-foot-tall booster. Engineers said the rocket was in the correct posture on the launch pad, indicating a computer software or sensor glitch.

Investigators blamed the Aug. 27 scrub on a slight time lag in the communications between the rocket's computer and the launch control center.

The launch team conducted a countdown rehearsal on Sunday with no problems.

JAXA issued a press release Monday announcing the first launch of the Epsilon rocket would occur no earlier than Saturday, Sept. 14, from the Uchinoura Space Center on the southern coast of Kyushu, the southernmost of Japan's main islands.

The solid-fueled Epsilon rocket will launch the Spectroscopic Planet Observatory for Recognition of Interaction of Atmosphere, an ultraviolet space telescope designed to observe the atmospheres of Venus and Mars.

The small satellite, which will be launched into low Earth orbit, will also study the magnetosphere of Jupiter.

Japanese officials say a computer aboard Japan's new Epsilon rocket detected a faulty sensor reading moments before it was supposed to lift off Tuesday, postponing the launch as engineers diagnose the cause of the last-minute glitch. Read our full story.

SCRUB. Launch will not occur today. We are awaiting word on what caused the countdown to be halted and when another launch attempt could be made.

ABORT. The countdown was halted some time before liftoff, and the Epsilon launcher remains on the launch pad. We will share more information as we receive it.

T-minus 60 seconds. The countdown is running on an automatic computer-controlled sequencer.

At T-minus 55 seconds, the Epsilon rocket will be switched to internal power. The launcher's pyrotechnic systems will be armed at T-minus 26 seconds. The launcher's computer will be switched to flight preparation mode at T-minus 22 seconds.

T-minus 2 minutes. JAXA reports the Epsilon rocket is ready to launch.

Coming up in the next two minutes, computers will prepare the Epsilon rocket for liftoff. The automatic countdown sequence is due to begin at T-minus 70 seconds.

T-minus 3 minutes. The current temperature at the launch site is 81 degrees Fahrenheit and there are light winds.

T-minus 5 minutes. There are no problems reported at this point in the countdown.

After liftoff, the rocket will be tracked by communications stations at the Uchinoura launch site, JAXA's Tanegashima Space Center southwest of the launch site, JAXA's tracking site on the Ogasawara Islands south of Tokyo, JAXA's ground station on Christmas Island in the Pacific Ocean, and a Swedish-owned antenna in Santiago, Chile.

T-minus 10 minutes. Today's mission is the first space launch from the Uchinoura Space Center since September 2006, when the final M-5 rocket took off with the Hinode solar observatory. Uchinoura is located in the Kagoshima prefecture on the southern shore of Kyushu, the southernmost of Japan's main islands.

T-minus 15 minutes. The final satellite launch sequence begins now. In a few moments, the 767-pound SPRINT-A payload will be switched to internal power and removed from ground electrical supplies. The battery will power the satellite until it extends its solar arrays, which extend 23 feet tip-to-tip.

T-minus 18 minutes. The latest report from the launch team indicates all parameters are "go" for an on-time launch at 0445 GMT (12:45 a.m. EDT; 1:45 p.m. Japan time).

The Epsilon rocket stands 80 feet tall, is 8.2 feet in diameter, and weighs about 200,000 pounds at the time of liftoff.

T-minus 20 minutes. If you do not see the live launch webcast, refresh this page and it should appear at the top.

T-minus 30 minutes. You can follow the launch with this timeline of major events and a map showing the rocket's ground track over the Pacific Ocean.

T-minus 60 minutes.

The Epsilon rocket is heralded by JAXA as a testbed for state-of-the-art technologies designed to make future launch vehicles more autonomous and easier to operate. Countdowns on future Epsilon missions could be nearly autonomous, with the rocket performing all preparatory steps and monitoring its own progress. If any problem develops, the rocket could alert ground teams or call an abort itself.

Later missions may also be permitted to launch with an autonomous destruct system to terminate the mission in the event the rocket encounters problems or flies off course.

Launch preparations are proceeding as planned for the first launch of Japan's Epsilon rocket at 0445 GMT (12:45 a.m. EDT; 1:45 p.m. Japan time).

The 80-foot Epsilon rocket is being removed from its protecting gantry-like enclosure now. The launcher will be rotated atop a pedestal over the launch pad's flame trench, then the rocket will be powered up for prelaunch testing.

The launch pad at Uchinoura, which was previously used by Japan's M-5 rocket program, is unique in that the rocket is housed inside a gantry during assembly, then the launcher and its umbilical tower rotate out of the protective structure and lock into position over the flame trench. Most launch pads feature either mobile assembly towers or "clean pad" designs, in which the launch vehicle moves to the launch site from an integration building hundreds of meters away.

A Japanese rocket designed to reduce the complexity and cost of satellite launches will take off on its inaugural flight Tuesday with a small telescope to study how the solar wind warps the atmospheres of nearby planets.

The Epsilon rocket is set to take off at 0445 GMT (12:45 a.m. EDT) Tuesday from the Uchinoura Space Center on the southern shore of Kyushu, the southernmost of Japan's main islands. Launch is scheduled for 1:45 p.m. local time.

The 80-foot-tall rocket is positioned on a hillside launch pad near the Pacific Ocean, poised to race skyward and head east from Uchinoura bound for an orbit with a high point of 1,150 kilometers, or 714 miles, a low point of 950 kilometers, or 590 miles, and an inclination of 31 degrees.

Japan approved development of the Epsilon rocket in 2010, giving the Japan Aerospace Exploration Agency a tight budget of 20.5 billion yen, or about $208 million, to fund the design and qualification of the three-stage launcher.

JAXA says Epsilon missions will ultimately fly for less than one-half the cost of a launch of its predecessor - the M-5 booster. Each Epsilon launch is projected to cost about 3.8 billion yen, or approximately $38 million, according to JAXA.

The Epsilon rocket also employs a streamlined processing and operations team. It took six weeks to prepare an M-5 rocket for launch, and JAXA says an Epsilon launch campaign will take seven days once the booster's first stage is stacked on the launch pad.

Launch controllers can also connect to the rocket using laptop computers to oversee launch preparations and the final countdown, and the Epsilon's own software is designed to check its health status without help from engineers.

With a government mandate to keep costs down, engineers used proven rocket motors for the Epsilon booster. Its first stage is based on the solid rocket booster used on Japan's larger H-2A and H-2B rockets, and it will consume 66.3 metric tons - 146,000 pounds - of solid propellant in less than 2 minutes.

Epsilon's solid-fueled second and third stage motors were used on the M-5 rocket. The rocket's basic three-stage configuration can loft payloads of more than 2,600 pounds into low Earth orbit.

The booster also uses the same launch pad as the M-5, which last flew in 2006. Engineers modified the launch pad by adding a 30-foot-tall pedestal and expanding the facility's flame trench.

A liquid-fueled stage will adjust the rocket's orbit during two firings before deploying the SPRINT-A spacecraft about 61 minutes after liftoff.

The 767-pound satellite's one-year mission is to observe the atmospheres of Mars and Venus, along with the immense magnetic field of Jupiter, to study how the planets respond to the solar wind, a stream of charged particles coming from the sun.

SPRINT-A stands for the Spectroscopic Planet Observatory for Recognition of Interaction of Atmosphere.

The craft's 20-centimeter, or 7.9-inch, telescope and will peer at Mars and Venus in extreme ultraviolet wavelengths to help researchers learn how the solar wind can strip a planet's atmosphere, prompting dramatic climate changes and possibly erasing life from its surface.

SPRINT-A will also look at Jupiter's giant magnetosphere, which swells ten times as large the sun due to an influx of plasma from erupting on volcanoes on Jupiter's moon Io.

The mission's objective is to determine the distribution of a planet's atmosphere and magnetosphere influenced by the solar wind.