Not that I'm aware of.
I'll warn you - having played both - that there will be issues in the conversion; at it's heart, Deathwatch is a munchkin's dream because Space Marines are That Damn Hard (TM).
The character stats and standard issue stuff you get verges on the ludicrous compared to Dark Heresy (which is more-or-less an equivalent; you may be working for the Inquisition but you are fundamentally 'bloke off the street' in the same way as Traveller).
This is achievable in terms of raw rules - Powered Armour = Battle Dress, Terminator Armour = Artillery Battle Dress, etc, etc.
Vehicles and weapons are easy enough, big monsters also (animal encounters, etc) and Traveller is easy enough to generate stuff for.
The big problems are:
1) Character Generation
Marine characters do not have substandard stats - just 'awesome', 'more awesome' and 'slightly less awesome but still freaking cool'. This is not Imperial-Marine-with-augmentations level; they are genetically modified so much that they are fundamentally not Homo Sapiens Sapiens anymore.
You don't get picked (or survive the process being picked) unless you're nails to start with, and a big wodge of standard skills are passed over by default.
I'd suggest using the Living Traveller points-buy system for characters, but with significantly more than 40 points to play with. No-one should start with any physical stat at less than 12, frankly.
Battle Dress/1
Recon/1
Stealth/1
Explosives/1
Drive (Ground)/1
Tactics (Military)/2
Gun Combat/2
Melee (Blade)/2
and many, many more.
2) Hordes
With characters this powerful, making an interesting threat is important. Tanks or big scary gribbly things are easy, but one thing Deathwatch includes is the concept of the Horde - essentially mass combat versus individuals; with heretics and hormagaunts being dangerous only because there's a crudload of them.
Traveller doesn't really include this concept for ground combat. It does, as it happens, haves something very similar for fleets in the form of the Barrage rules but they're a bit convoluted to try and adapt.
Some ability to combine fire might be useful - I'd consider counting a group of people firing as a single burst mode shot with the auto characteristic equal to the number of firers (or half the number of firers, or whatever), and can hit with suppressing fire as a group. The good thing is that you needn't bother to track damage in terms of END, DEX and STR damage - if it fights in a horde it categorically will not survive a hit from a bolt round.
For that matter, you might use the Mass Combat rules from Mercenary - count each Marine as a TL15 Elite Heavy Infantry Unit, with an arbitrary 'strength' equal to however many 'wounds' you want them to have (I'd suggest somewhere in the 5-10 range, making them the equivalent of a platoon, and giving the 1-5 range where they are discernably 'wounded' and less effective)