IRIS Launch Blog

IRIS Launch Coverage

Artists' concept of IRIS spacecraft in orbitNASA's Interface Region Imaging Spectrograph (IRIS) spacecraft began its two-year mission with a successful launch at 7:27 p.m. PDT aboard an Orbital Sciences Pegasus XL rocket launched from California's Vandenberg Air Force Base. From its position in polar, sun-synchronous orbit, the 403-pound IRIS satellite will investigate the sun's lower atmosphere in unprecedented detail.

Note: Times provided in blog posts are given in Eastern time; timestamps are provided in your local time.

Launch Blog Concludes with IRIS in Orbit

Thu, 27 Jun 2013 10:57:54 PM EDT

NASA Launch Manager Tim Dunn reports that the mission team has made initial contact with the IRIS spacecraft through the Tracking and Data Relay Satellite System and received good data in return. The telescope is right on track and its solar arrays are deploying.

"We've got a very happy spacecraft on orbit and a thrilled launch team on the ground," Dunn said.

With this good news, NASA's Launch Blog for IRIS comes to an end. To keep up with the latest news from this mission, visit http://www.nasa.gov/iris.


IRIS Flying Solo

Thu, 27 Jun 2013 10:42:30 PM EDT

Success! The IRIS spacecraft is flying solo after a 13-minute ride into orbit aboard a Pegasus XL rocket.


Third Stage Burnout

Thu, 27 Jun 2013 10:38:28 PM EDT

The Pegasus rocket's third-stage burn is complete. Launch and mission managers are standing by for deployment of the IRIS spacecraft.


Third Stage Ignition

Thu, 27 Jun 2013 10:37:13 PM EDT

Stage two separation and stage three ignition. This is a brief burn lasting one minute and 9 seconds.


Second Stage Burnout; Entering Coast Phase

Thu, 27 Jun 2013 10:30:54 PM EDT

The Pegasus rocket's second-stage engine shut down as expected and the vehicle is entering a coast phase.


Fairing Separation

Thu, 27 Jun 2013 10:30:13 PM EDT

Right on schedule, the rocket's payload fairing separated and fell away, leaving the IRIS spacecraft exposed to the outside environment. The Pegasus rocket is performing well as the second-stage engine continues its burn.


First Stage Burnout and Separation; Second Stage Ignition

Thu, 27 Jun 2013 10:29:42 PM EDT

The Pegasus rocket has passed the area of maximum aerodynamic pressure known as Max Q. The first-stage engine burn ended on time. With the first stage safely jettisoned, the second-stage burn is in progress. This is a one-minute, 13-second burn.


Pegasus is Away!

Thu, 27 Jun 2013 10:27:54 PM EDT

3, 2, 1, drop! Pegasus is free of the Stargazer aircraft -- and the rocket's first burn is under way. IRIS is heading toward a polar, sun-synchronous Earth orbit.


Standing By for Launch

Thu, 27 Jun 2013 10:24:51 PM EDT

In the final minute of captive carry, the rocket's fin battery will be activated and the pilot will confirm Pegasus is "go" for launch. At drop time, Pegasus will be released from the belly of the Stargazer, and the rocket's first-stage motor will ignite five seconds later.


T-4 Minutes and Counting

Thu, 27 Jun 2013 10:22:37 PM EDT

Orbital Sciences Launch Conductor Adam Lewis has polled his team and given clearance to proceed with launch. T-4 minutes and counting.


NASA 'Go' for Launch

Thu, 27 Jun 2013 10:20:14 PM EDT

NASA Launch Manager Tim Dunn has performed his final launch readiness poll and given the team the green light to continue through the final minutes of the countdown.


T-10 Minutes and Counting

Thu, 27 Jun 2013 10:18:04 PM EDT

Only ten minutes left until the opening of tonight's launch window.


T-15 Minutes and Counting

Thu, 27 Jun 2013 10:12:41 PM EDT

There are 15 minutes remaining until the scheduled release of the Pegasus XL rocket from the Stargazer L-1011 carrier aircraft.


A Big Mission in a Small Package

Thu, 27 Jun 2013 10:03:27 PM EDT

Although IRIS boasts a lot of capability, it's packed into a compact satellite: the spacecraft measures only 86 inches in length. Its two solar arrays, once deployed, will extend to a width of 12 feet.


Stargazer Passes Next Waypoint

Thu, 27 Jun 2013 09:58:01 PM EDT

Stargazer is passing the "P-Power" waypoint, which will bring the aircraft directly below the drop point on its way into the racetrack pattern.


The Pegasus Rocket

Thu, 27 Jun 2013 09:46:48 PM EDT

Orbital Sciences' Pegasus rocket launched for the first time in April 1990 and has built a solid history of success. The 55.6-foot-long Pegasus XL rocket is a three-stage, solid-fueled launch vehicle that specializes in carrying payloads weighing no more than 1,000 pounds into low-Earth orbit. Only four feet in diameter, the rocket has a 22-foot wingspan.

NASA's most recent spacecraft to ride inside a Pegasus XL was the NuSTAR observatory, which launched June 13, 2012, from the Kwajalein Atoll in the Pacific Ocean.

Getting back to tonight's IRIS launch, the Pegasus remains secured to the bottom of the Stargazer carrier aircraft. Launch remains scheduled for 10:27 p.m. This gives the Stargazer crew time to reach the necessary 39,000-foot altitude and maneuver into position to release the rocket.


Stargazer Begins Climb-Out

Thu, 27 Jun 2013 09:44:30 PM EDT

The aircraft is passing the first waypoint on today's flight path, "P-Climb," which defines the climb-out segment of captive carry. Captain Don Walter and his crewmates are working from the climb/cruise checklist as they continue guiding Stargazer toward the necessary altitude and drop point.


IRIS to Train its Eye on the Sun's Lower Atmosphere

Thu, 27 Jun 2013 09:34:26 PM EDT

From a high perch more than 380 miles above Earth, the IRIS observatory will take a close look at how energy moves in the sun's interface region.

The sun's visible surface -- or photosphere -- is a scorching 11,000 degrees Fahrenheit. Above it is the upper corona, burning in the millions of degrees. Between the photosphere and the upper corona lies the interface region. While this area is believed to have a major influence on the sun-Earth relationship, it hasn't yet been studied in detail, and scientists aim to change that with this mission.

Ultraviolet emissions streaming from the sun affect Earth's climate as well as the space environment that surrounds us. The IRIS spacecraft, with its ultraviolet telescope, is equipped to take high-resolution photos and spectrometry, offering a look at how energy and plasma move through the varying layers of the solar atmosphere. When combined with 3D modeling, these observations could greatly increase our understanding of our nearest star.


Stargazer is Airborne

Thu, 27 Jun 2013 09:30:53 PM EDT

Wheels up! Stargazer, Orbital Sciences' modified L-1011 aircraft, is climbing into the evening sky from Vandenberg Air Force Base in California. Takeoff marks the beginning of the captive-carry portion of the flight. During the next hour, the aircraft will pass a series of waypoints and eventually enter a racetrack pattern that will take it into the "drop box," a defined area containing the preferred drop point. Tonight the rocket will be released from an altitude of 39,000 feet about 100 miles northwest of Vandenberg, over the Pacific Ocean.

Following the drop, Pegasus will free-fall for five seconds, then its first-stage motor will ignite and its flight will begin. The IRIS spacecraft separates from the rocket 13 minutes after launch.


'Go' for Takeoff

Thu, 27 Jun 2013 09:26:19 PM EDT

Orbital Sciences Launch Conductor Adam Lewis and NASA Launch Manager Tim Dunn have checked in with their teams and the L-1011 is verified ready for takeoff.

An F-18 chase plane took off about two minutes ahead of the L-1011.


Carrier Aircraft Moving to Runway

Thu, 27 Jun 2013 09:15:46 PM EDT

The Stargazer aircraft is heading toward the end of the runway. On board, Captain Don Walter is joined by Pilot Eb Harris and Flight Engineer Bob Taylor.

Launch officials will poll their teams in just a few minutes, and if everyone is ready, the aircraft will be cleared for departure.


A Coast-to-Coast Effort

Thu, 27 Jun 2013 09:12:16 PM EDT

Launch managers and controllers are stationed at Vandenberg, but support teams are monitoring the countdown from Florida's Cape Canaveral Air Force Station. Tonight's launch blog originates from the Mission Director's Center inside Hangar AE at the Florida site. The agency's Launch Services Program is based at neighboring Kennedy Space Center.

Please note that throughout coverage, milestone times will be given in EDT, but each blog post is timestamped with your local time.


Countdown Status and Weather Update

Thu, 27 Jun 2013 09:08:17 PM EDT

At 5 p.m. EDT, launch controllers reported to their consoles at Vandenberg to prepare for the start of the countdown at 5:30 p.m. The captain and crew of the L-1011 carrier aircraft are working from the engine start and pre-taxi checklist, aiming for a takeoff at 9:27 p.m.

According to 1st Lt. Jennifer Kelley of the U.S. Air Force 30th Operations Support Squadron, tonight's weather is forecast to be favorable, with only a 20 percent chance of conditions prohibiting launch.


IRIS, Pegasus Ready to Fly

Thu, 27 Jun 2013 09:00:43 PM EDT

Tonight at Vandenberg Air Force Base in California, an Orbital Sciences Pegasus XL rocket is ready to carry NASA's Interface Region Imaging Spectrograph spacecraft into Earth orbit. The IRIS spacecraft, as it's called, is embarking on a two-year mission to study the sun's interface region -- a mysterious portion of the solar atmosphere that influences ultraviolet emissions that affect us here on Earth.

A Pegasus launch is different from most rocket launches. Rather than lifting off vertically from a ground-based launch pad, Pegasus is carried aloft by a modified L-1011 aircraft named Stargazer, which releases the rocket at a specific drop point. Tonight's launch of the Pegasus and IRIS is scheduled for 10:27 p.m. EDT at the opening of a five-minute window of opportunity.

Our coverage is just beginning, so stay with us for the latest from the countdown.


Launch Day Arrives

Thu, 27 Jun 2013 03:57:51 PM EDT

Live countdown coverage begins tonight at 6 p.m. PDT, 9 p.m. EDT. Join us!

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Page Last Updated: September 30th, 2013
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