diff --git a/.gitignore b/.gitignore
index e378dc8..8533b16 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,4 @@
 *.2*
 *.4*
 *.bsp
+Manifest.toml
diff --git a/Project.toml b/Project.toml
new file mode 100644
index 0000000..d0e1b93
--- /dev/null
+++ b/Project.toml
@@ -0,0 +1,18 @@
+name = "JPLEphemeris"
+uuid = "30a7bc16-7fba-505b-b600-cae92896a3fe"
+
+[deps]
+AstroBase = "e1773a3a-3ab2-51da-b25a-65b4161c689f"
+LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
+Mmap = "a63ad114-7e13-5084-954f-fe012c677804"
+Reexport = "189a3867-3050-52da-a836-e630ba90ab69"
+
+[compat]
+Reexport = "≥ 0.2.0"
+julia = "≥ 0.7.0"
+
+[extras]
+Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
+
+[targets]
+test = ["Test"]
diff --git a/REQUIRE b/REQUIRE
deleted file mode 100644
index 57a9938..0000000
--- a/REQUIRE
+++ /dev/null
@@ -1,3 +0,0 @@
-julia 0.7
-AstroBase
-Reexport 0.2.0
diff --git a/benchmark/benchmark.jl b/benchmark/benchmark.jl
index 232a326..2baa804 100644
--- a/benchmark/benchmark.jl
+++ b/benchmark/benchmark.jl
@@ -8,10 +8,10 @@ Random.seed!(430)
 function runner_ep(times)
     pos = zeros(3)
     vel = zeros(3)
-    position_velocity!(pos, vel, spk, times[1], luna, mercury)
+    state!(pos, vel, spk, times[1], luna, mercury)
     total = 0.0
     for t in times
-        time = @elapsed position_velocity!(pos, vel, spk, t, luna, mercury)
+        time = @elapsed state!(pos, vel, spk, t, luna, mercury)
         total += time
     end
     print_time(total / n)
diff --git a/src/spk.jl b/src/spk.jl
index a726a27..df8cffd 100644
--- a/src/spk.jl
+++ b/src/spk.jl
@@ -1,14 +1,14 @@
 using LinearAlgebra: transpose!
 using AstroBase: NAIFId, TDBEpoch, from_naifid, julian_twopart, value, SECONDS_PER_DAY
 
-import AstroBase.Interfaces:
+import AstroBase.Ephemerides:
     AbstractEphemeris,
     position,
     position!,
     velocity,
     velocity!,
-    position_velocity,
-    position_velocity!
+    state,
+    state!
 
 export SPK,
     segments,
@@ -17,8 +17,8 @@ export SPK,
     position!,
     velocity,
     velocity!,
-    position_velocity,
-    position_velocity!
+    state,
+    state!
 
 const SIZE_FLOAT64 = sizeof(Float64)
 
@@ -236,7 +236,7 @@ end
 end
 
 
-@inline function position_velocity!(pos,
+@inline function state!(pos,
                                     vel,
                                     spk::SPK,
                                     seg::Segment,
@@ -265,7 +265,6 @@ end
     segments[origin][target], sign
 end
 
-
 function position!(pos, spk::SPK, ep::TDBEpoch, from::NAIFId, to::NAIFId)
     seg, sign = findsegment(spk.segments, from, to)
     jd1, jd2 = value.(julian_twopart(ep))
@@ -278,9 +277,9 @@ function velocity!(vel, spk::SPK, ep::TDBEpoch, from::NAIFId, to::NAIFId)
     velocity!(vel, spk, seg, sign, jd1, jd2)
 end
 
-function position_velocity!(pos, vel, spk::SPK, ep::TDBEpoch, from::NAIFId, to::NAIFId)
+function state!(pos, vel, spk::SPK, ep::TDBEpoch, from::NAIFId, to::NAIFId)
     seg, sign = findsegment(spk.segments, from, to)
     jd1, jd2 = value.(julian_twopart(ep))
-    position_velocity!(pos, vel, spk, seg, sign, jd1, jd2)
+    state!(pos, vel, spk, seg, sign, jd1, jd2)
 end
 
diff --git a/test/basic.jl b/test/basic.jl
index 0b99e45..71dbe37 100644
--- a/test/basic.jl
+++ b/test/basic.jl
@@ -33,7 +33,7 @@ spk = SPK("$path/de430.bsp")
     @testset for (a, b) in zip(JPLEphemeris.list_segments(spk), de430segments)
         @test a == b
     end
-    @testset for (func, ref) in zip((position, velocity, position_velocity), (r_ref, v_ref, rv_ref))
+    @testset for (func, ref) in zip((position, velocity, state), (r_ref, v_ref, rv_ref))
         res = func(spk, ep, ssb, mercury_barycenter)
         @test all(res .≈ ref)
         res = func(spk, ep, mercury_barycenter, ssb)
diff --git a/test/kernels.jl b/test/kernels.jl
index 2adacce..88769f8 100644
--- a/test/kernels.jl
+++ b/test/kernels.jl
@@ -61,7 +61,7 @@ end
 function teststate(kernel, tdb, origin, target)
     origin = id_to_body(origin)
     target = id_to_body(target)
-    rv = vcat(position_velocity(kernel, tdb, origin, target)...)
+    rv = vcat(state(kernel, tdb, origin, target)...)
     # From km/s to km/day
     rv[4:6] .*= 86400.0
     # From km to AU