March 10, 2015

With Trajectory Correction, NASA’s New Horizons Homes in on Pluto

A 93-second thruster burst today slightly adjusted the New Horizons spacecraft’s trajectory toward Pluto.

This was the first maneuver of New Horizons’ approach phase to Pluto; it was planned to slow the spacecraft’s velocity by just 1.14 meters per second – barely a tap on the brakes for a probe moving about 14.5 kilometers per second – and moved its July 14 arrival time back on schedule with a change from the pre-burn course of 14 minutes and 30 seconds. It will also shift the course “sideways” (if looking from Earth) by 3,442 kilometers (2,139 miles) by July 14, sending the spacecraft toward a desired flyby close-approach target point. The shift was based on the latest orbit predictions of Pluto and its largest moon Charon, estimated from various sources, including optical-navigation images of the Pluto system taken by New Horizons in January and February.

Using commands transmitted to the spacecraft on March 8, the thrusters began firing at 5:15 a.m. EDT, and stopped just 93 seconds later. Initial telemetry later indicated the spacecraft was healthy and fired on command reached the New Horizons Mission Operations Center at APL through NASA’s Deep Space Network at noon EDT; detailed data from the spacecraft’s Guidance and Control system – which will show the team how accurately the maneuver performed as designed – is expected later today.

Short Bursts
Trajectory Correction Maneuver 15B2

  • Length: 93 seconds
  • Result: slowed New Horizons velocity by 1.14 meters/second; delayed Pluto arrival time by 14 minutes 30 seconds; shifted trajectory toward desired flyby close-approach point.
  • New Horizons approximate distance from Earth: 3 billion miles; 4.8 billion kilometers (32.28 astronomical units)
  • New Horizons approximate distance from Pluto: 93 million miles; 149 million kilometers (1 au)
  • Time for signal to reach Earth: 4 hours, 28 minutes, 31 seconds
  • Primary communications: NASA Deep Space Network Canberra Station, Australia (70-meter antenna)

Fast Fact: After the maneuver New Horizons entered “spin mode” – a more efficient mode for sending data back to Earth – where it will remain until April 4.