New Year, New Horizons probe flyby

Happy new year to you all.

The big science story as we enter 2019 has to be the New Horizons probe flyby of Ultima Thule. The science data will undoubtedly be fascinating, but as an engineer what appeals to me is the technical challenge of sending a spacecraft over 6.5 billion km to an object only 20km across with pin-point accuracy.

All navigation comes down to three elements, position, velocity and time, so I was not surprised to learn that synchronization is a key component. The entire operation of the spacecraft is synchronized to UT (Universal Time), so that actions can be precisely scheduled by the ground controllers. Scheduling in advance is obviously very important when commands take six hours to arrive at the spacecraft. Also, science observations require pointing the instruments at the target, which means the communications antenna can’t be pointed at earth simultaneously. All observations must be programmed ahead.

Ultima Thule

The heart of the scheduling systems are two redundant ultra-stable ovenized oscillators, accurate to a part in 1013 over 10s. That’s about 100x better than most commercial earthbound oscillators. The oscillators are locked to UT to within ±4s. This may not sound much to those of us used to dealing with sub-microsecond synchronization, but bear in mind that the mission launched 13 years ago, the current round-trip communications time is over 12 hours, and the spacecraft is travelling at 14km/s. Therefore the communications delay changes by several microseconds every second and will be highly asymmetric – pretty tough for symmetric time-transfer mechanisms such as PTP or NTP. On-board, the instruments are all synchronized to within 10ms to allow correlation of results between different instruments.

There’s plenty more information out there on the internet, but one good summary is at

Tim Frost
Strategic Technology Manager

Recent Blogs

Related Blogs

Four Boardroom Members

How to Optimise Your IT Network and Spend

Feb 06, 2019
Network emulation can be a key tool to overcome barriers in getting the most out of your…
4322 Read more

Responding to IT Network Issues

Jan 22, 2019
If simple remedial scripts are not enough to fix an IT network issue, a more…
4967 Read more

Keeping Audiences 'In the Moment'

Nov 16, 2018
Today’s broadcast audiences are seeking more. They want user defined, on demand content.…
1638 Read more

Archived Blogs

1419 More
1632 More

Timing not Telecoms

Nov 08, 2016
1076 More

5G Coming Soon

Aug 22, 2016
1092 More

What is 1588 PTP?

Aug 04, 2016
1408 More

5G on the Horizon

Aug 01, 2016
1103 More
1108 More

What is a PTP Clock?

Apr 09, 2016
1361 More

What is Time Error?

Oct 21, 2015
1098 More

LTE-A & VoLTE Rollout

Sep 22, 2015
1064 More

LTE Picks Up Speed

Aug 22, 2015
1031 More

What is the Time?

Aug 22, 2015
1068 More

Mobile and Sync

Aug 22, 2015
1030 More

What is SyncE?

Aug 22, 2015
2117 More
1164 More

Microwave Update

Aug 22, 2015
1126 More

Unravelling Standards

Aug 22, 2015
1109 More

Partial Progress?

Aug 22, 2015
1038 More

Interpreting ITU

Aug 22, 2015
1045 More

Confusion Rules!

Aug 22, 2015
1099 More

Basestations Need Sync

Aug 22, 2015
1084 More

ITSF 2015 Edinburgh

Aug 22, 2015
1029 More

India to Follow China?

Aug 07, 2015
1047 More

Click your area of interest below for more tutorials and real-world case studies.